As filed with the United States Securities and Exchange Commission on April 1, 2019

Registration No. 333-          

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form S-3

Registration Statement

Under

The Securities Act of 1933

SEACOR Marine Holdings Inc.

(Exact name of registrant as specified in its charter)

12121 Wickchester Lane, Suite 500

Houston, Texas 77079

(346) 980-1700

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

John Gellert

President and Chief Executive Officer

SEACOR Marine Holdings Inc.

12121 Wickchester Lane, Suite 500

Houston, Texas 77079

(346) 980-1700

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box:  ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box:  ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  ☐

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☒

CALCULATION OF REGISTRATION FEE

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with section 8(a) of the Securities Act or until the registration statement shall become effective on such date as the Commission acting pursuant to said section 8(a) may determine.

The information in this prospectus is not complete and may be changed. The selling stockholders may not sell the securities described herein until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell the securities described herein and neither we nor the selling stockholders are soliciting offers to buy such securities in any state where such offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED APRIL 1, 2019

PROSPECTUS

653,872 Shares of Common Stock

This prospectus relates to an offer and sale of up to 653,872 shares of common stock, par value $0.01 per share (“common stock”), of SEACOR Marine Holdings Inc., by the selling stockholders. The selling stockholders may offer shares of our common stock, from time to time, in a number of different ways and at varying prices. We will not receive any proceeds from the sale of common stock by the selling stockholders covered by this prospectus. We will bear all costs, expenses and fees in connection with the registration of the shares. The selling stockholders will bear all commissions and discounts, if any, attributable to the sale of common stock.

This prospectus provides you with a general description of the securities that our selling stockholders may offer. To the extent required by applicable law or regulation, each time securities are offered, the selling stockholders are required to provide this prospectus and a prospectus supplement. If a prospectus supplement is required, such prospectus supplement will contain more specific information about the offering and the terms of the securities being offered by our selling stockholders. A prospectus supplement may also add, update or change information contained in this prospectus.

The selling stockholders may offer and sell these securities to or through one or more underwriters, dealers and agents, or directly to purchasers, on a continuous or delayed basis. To the extent required, the specific terms of any securities the selling stockholders offer will be included in a supplement to this prospectus. Any such prospectus supplement will also describe the specific manner in which our selling stockholders will offer the securities.

Investing in our securities involves risks. You should carefully consider the risks described under “Risk Factors” on page 2 of this prospectus, as well as the other information contained or incorporated by reference in this prospectus and the applicable prospectus supplement, before making a decision to invest in our securities.

Our common stock is traded on The New York Stock Exchange (the “NYSE”) under the symbol “SMHI.” The last reported sales price of our common stock on the NYSE on March 29, 2019 was $13.31 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities described herein or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is                     , 2019

TABLE OF CONTENTS

This prospectus is part of a registration statement that we have filed with the Securities and Exchange Commission, or the SEC. In making your investment decision, you should rely only on the information contained in this prospectus, any prospectus supplement and the documents that we incorporate by reference. We have not authorized anyone to provide you with any other information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making an offer of the securities described herein in any jurisdiction where the offer is not permitted.

You should not assume that the information contained in this prospectus or any prospectus supplement is accurate as of any date other than the date on the front of the respective document. You should not assume that the information contained in the documents incorporated by reference in this prospectus or any prospectus supplement is accurate as of any date other than the respective dates of those documents. Our business, financial condition, results of operations and prospects may have changed since those dates.

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we have filed with the SEC using a “shelf” registration or continuous offering process. Under this shelf registration process, the selling stockholders may, from time to time, sell up to 653,872 shares of our common stock that we have issued to the selling stockholders.

This prospectus generally describes SEACOR Marine Holdings Inc. and, provides you with a general description of the securities the selling stockholders may offer. Each time any of the selling stockholders sell common stock under this prospectus, such selling stockholder will provide you with this prospectus and, to the extent required, a prospectus supplement that will contain more information about the specific terms of the offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. Each such prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you), if any, may also add, update or change information contained in this prospectus or in documents incorporated by reference into this prospectus. We urge you to carefully read this prospectus, any applicable prospectus supplement, if any, and any related free writing prospectus, together with the information incorporated herein by reference as described under the headings “Where You Can Find More Information” and “Documents Incorporated By Reference” before buying any of the securities being offered. We or the selling stockholders will deliver a prospectus supplement with this prospectus, to the extent appropriate, to update the information contained in this prospectus

You should rely only on the information contained or incorporated by reference in this prospectus, any applicable prospectus supplement and any related free writing prospectus. We have not authorized anyone to provide you with any information in addition to or different from that contained in this prospectus, any applicable prospectus supplement and any related free writing prospectus. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus that we may authorize to be provided to you. You must not rely on any unauthorized information or representation. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate only as of the date on the front of the document and that any information incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, any applicable prospectus supplement or any related free writing prospectus, or any sale of a security.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find More Information.”

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, including the documents incorporated by reference herein contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Such forward-looking statements concern management’s expectations, strategic objectives, business prospects, anticipated economic performance and financial condition and other similar matters and involve significant known and unknown risks, uncertainties and other important factors that could cause the actual results, performance or achievements of results to differ materially from any future results, performance or achievements discussed or implied by such forward-looking statements. All of these forward-looking statements constitute the Company’s cautionary statements under the Private Securities Litigation Reform Act of 1995. The words “anticipate,” “estimate,” “expect,” “project,” “intend,” “believe,” “plan,” “target,” “forecast” and similar expressions are intended to identify forward-looking statements. Forward-looking statements speak only as of the date of the document in which they are made. The Company disclaims any obligation or undertaking to provide any updates or revisions to any forward-looking statement to reflect any change in the Company’s expectations or any change in events, conditions or circumstances on which the forward-looking statement is based. Risks that may affect forward-looking statements include, but are not necessarily limited to, those relating to:

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You should not place undue reliance on our forward-looking statements because the matters they describe are subject to known and unknown risks, uncertainties and other unpredictable factors, many of which are beyond our control. Our forward-looking statements are based on the information currently available to us and speak only as of the date on the cover of this prospectus. New risks and uncertainties arise from time to time, and it is impossible for us to predict these matters or how they may affect us. We have included important factors in the cautionary forward-looking statements included in this prospectus, particularly in the section of this prospectus entitled “Risk Factors,” which we believe over time, could cause our actual results, performance or achievements to differ from the anticipated results, performance or achievements that are expressed or implied by our forward-looking statements. We have no duty to, and do not intend to, update or revise the forward-looking statements in this prospectus after the date of this prospectus except to the extent required by the federal securities laws. You should consider all risks and uncertainties disclosed in our filings with the Securities and Exchange Commission, or the SEC, described in the sections of this prospectus entitled “Where You Can Find More Information” and “Documents Incorporated By Reference,” all of which are accessible on the SEC’s website at www.sec.gov.

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RISK FACTORS

An investment in our securities involves a significant degree of risk. Before you invest in our securities you should carefully consider those risk factors included in our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, which are incorporated herein by reference, and those risk factors that may be included in any applicable prospectus supplement, together with all of the other information included in this prospectus, any prospectus supplement and the documents we incorporate by reference, in evaluating an investment in our securities. If any of the risks discussed in the foregoing documents were to occur, our business, financial condition, results of operations and cash flows could be materially adversely affected. For more information on our SEC filings, please see the sections entitled “Where You Can Find More Information” and “Documents Incorporated by Reference.” Please also read the section entitled “Cautionary Statement Regarding Forward-Looking Statements.”

USE OF PROCEEDS

This prospectus relates to the offer and sale from time to time of 653,872 shares of common stock for the account of the selling stockholders referred to in this prospectus. We will not receive any proceeds from any sale of shares of common stock by the selling stockholders.

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DESCRIPTION OF CAPITAL STOCK

General

Our authorized capital stock consists of 60,000,000 shares of common stock, par value $0.01 per share, and 10,000,000 shares of undesignated preferred stock, $0.01 par value per share, of which no preferred shares are issued or outstanding.

The following summary description of our capital stock is based on the provisions of our Certificate of Incorporation and Bylaws and the applicable provisions of the Delaware General Corporation Law (“DGCL”). This information is qualified entirely by reference to the applicable provisions of our Certificate of Incorporation, Bylaws and the DGCL. For information on how to obtain copies of our Certificate of Incorporation and Bylaws, please see “Where You Can Find More Information” and “ Documents Incorporated By Reference.”

Common Stock

As of March 15, 2019, there were 21,070,529 shares of our common stock outstanding. The holders of our common stock are entitled to the following rights.

Voting Rights

Holders of our common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders, and do not have cumulative voting rights. The common stock votes together as a single class. Directors will be elected by a plurality of the votes of the shares of common stock present in person or by proxy at a meeting of stockholders and voting for nominees in the election of directors. Except as otherwise provided in our Certificate of Incorporation or required by law, all matters to be voted on by our stockholders must be approved by a majority of the shares present in person or by proxy at a meeting of stockholders and entitled to vote on the subject matter.

Dividend Rights

Holders of common stock are entitled to receive proportionately any dividends as may be declared by our board of directors, subject to any preferential dividend rights of outstanding preferred stock.

Liquidation Rights

Upon our liquidation, dissolution or winding up, the holders of common stock are entitled to receive proportionately our net assets available after the payment of all debts and other liabilities and subject to the prior rights of any outstanding preferred stock.

Other Rights

Holders of common stock have no preemptive, subscription, redemption or other conversion rights and do not have any sinking fund provisions. The rights, preferences and privileges of holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock which we may designate and issue in the future.

Shares of our common stock are not convertible into any other shares of our capital stock.

Preferred Stock

As of March 15, 2019, there were no shares of our preferred stock outstanding.

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Pursuant to our Certificate of Incorporation, our board of directors has the authority, without further action by the stockholders (unless such stockholder action is required by applicable law or stock exchange listing rules), to designate and issue up to 10,000,000 shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, to fix the designations, powers, preferences, privileges and relative participating, optional or special rights and the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, voting rights, terms of redemption and liquidation preferences, any or all of which may be greater than the rights of the common stock, and to increase or decrease the number of shares of any such series, but not below the number of shares of such series then outstanding.

The board of directors, without stockholder approval, can issue preferred stock with conversion or other rights that could adversely affect the voting power and other rights of the holders of common stock. Preferred stock could be issued quickly with terms designed to delay or prevent a change in control of our company or make removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of the common stock and may adversely affect the voting power of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation.

Qualifications for Ownership

The Company is subject to regulation under the Jones Act and related U.S. cabotage laws, which restrict ownership and operation of vessels in the U.S. coastwise trade (i.e., trade between points in the United States), including the transportation of cargo. Subject to limited exceptions, the Jones Act requires that vessels engaged in U.S. coastwise trade be built in the United States, registered under the U.S.-flag, manned by predominantly U.S. crews, and owned and operated by U.S. citizens within the meaning of the Jones Act. Violation of the Jones Act could prohibit operation of vessels in the U.S. coastwise trade during the period of such non-compliance, result in material fines and subject Company vessels to seizure and forfeiture.

To facilitate compliance with the Jones Act, the Company’s Certificate of Incorporation and Bylaws: (i) limit (a) the aggregate percentage ownership by non-U.S. citizens of any class of the Company’s capital stock (including common stock) to 22.5% of the outstanding shares of each such class to ensure that ownership by non-U.S. citizens will not exceed the maximum percentage permitted by applicable maritime law (presently 25%) but authorize the Company’s board of directors, under certain circumstances, to increase the foregoing percentage to not more than 24% and (b) ownership of shares of any class or series of its capital stock by a single non-U.S. citizen (and any other non-U.S. citizen whose ownership position would be aggregated with such non-U.S. citizen for purposes of the Jones Act) to not more than the Permitted Percentage; (ii) allow for the institution of a dual stock certification system to help determine such ownership; (iii) provide that any issuance or transfer of shares in excess of the Permitted Percentage shall be ineffective as against the Company and that neither the Company nor its transfer agent shall register such purported issuance or transfer of shares or be required to recognize the purported transferee or owner as a stockholder of the Company for any purpose whatsoever except to exercise the Company’s remedies under the Certificate of Incorporation; (iv) provide that any excess shares above the Permitted Percentage shall not have any voting or dividend rights; (v) permit the Company to redeem or transfer to a charitable trust any such excess shares; and (vi) permit the board of directors to make such reasonable determinations as may be necessary to ascertain such ownership and implement such limitations. In addition, the Company’s Bylaws provide (w) that the number of non- U.S. citizen directors shall not exceed a minority of the number necessary to constitute a quorum for the transaction of business, (x) for an increase in the number of directors necessary to constitute a quorum when the number of non-U.S. citizen directors is equal to or greater than 50% of the number of directors present at a meeting, (y) that the President and the Chief Executive Officer of the Company must be a U.S. citizen and (z) that any non-U.S. citizen officer is restricted from acting in the absence or disability of the chairman of the board of directors, the Chief Executive Officer or the President.

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Delaware Anti-Takeover Law and Provisions of our Certificate of Incorporation and Bylaws

Section 203 of the Delaware General Corporate Law.

We are subject to the provisions of Section 203 of the Delaware General Corporation Law (“Section 203”). In general, Section 203 prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a three-year period following the time that this stockholder becomes an interested stockholder, unless the business combination is approved in a prescribed manner. A “business combination” includes, among other things, a merger, asset or stock sale or other transaction resulting in a financial benefit to the interested stockholder. An “interested stockholder” is a person who owns 15% or more of the corporation’s outstanding stock, or an affiliate or associate of the corporation who did own 15% or more of the corporation’s voting stock within three years prior to the determination of interested stockholder status. Under Section 203, a business combination between a corporation and an interested stockholder is prohibited unless it satisfies one of the following conditions:

A Delaware corporation may opt out of Section 203 either with an express provision in its original certificate of incorporation or in an amendment to its certificate of incorporation or bylaws approved by its stockholders. However, we have not opted out, and do not currently intend to opt out, of this provision. The statute could prohibit or delay mergers or other takeover or change in control attempts and, accordingly, may discourage attempts to acquire us.

Certificate of Incorporation and Bylaws

Our Certificate of Incorporation and Bylaws contain provisions that may delay, defer or discourage another party from acquiring control of us. These provisions, which are summarized below, discourage coercive takeover practices or inadequate takeover bids. These provisions are designed to encourage persons seeking to acquire control of us to first negotiate with our board of directors, which we believe may result in an improvement of the terms of any such acquisition in favor of our stockholders. However, they also give our board of directors the power to discourage acquisitions that some stockholders may favor.

Filling Vacancies on the Board of Directors.

In accordance with Article II, Section 12 of our Bylaws, any vacancy on our board of directors, however occurring, including a vacancy resulting from an increase in the size of our board of directors, may only be filled by the affirmative vote of a majority of our directors then in office even if less than a quorum. Any director appointed to fill a vacancy will hold office until the next election of directors or until their successors are duly elected and qualified.

Meetings of Stockholders.

Our Bylaws provide that only a majority of the members of our board of directors then in office or the Chairman of the board of directors or the President may call special meetings of the stockholders and only those

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matters set forth in the notice of the special meeting may be considered or acted upon at a special meeting of stockholders. Our Bylaws limit the business that may be conducted at an annual meeting of stockholders to those matters properly brought before the meeting.

Advance Notice Requirements

Our Bylaws establish an advance notice procedure for stockholders to make nominations of candidates for election as directors or to bring other business before an annual meeting of our stockholders. The Bylaws provide that any stockholder wishing to nominate persons for election as directors at, or bring other business before, an annual meeting must deliver to our secretary a written notice of the stockholder’s intention to do so. To be timely, the stockholder’s notice must be delivered to us not later than the 120th day nor earlier than the 150th day prior to the anniversary date of the preceding annual meeting. If there was no such prior annual meeting, then a stockholder’s notice must be delivered not earlier than the close of business on the 150th day nor later than the 120th day prior to the date which represents the second Tuesday in May of the current year. In the event that the date of the annual meeting is more than 25 days before or after such anniversary date, then, to be considered timely, notice by the stockholders must be received not later than the close of business on the 10th day following the date on which public announcement of the date of such meeting is first made by us.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is American Stock Transfer and Trust Company, LLC, 6201 15th Avenue, Brooklyn, NY 11219.

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SELLING STOCKHOLDERS

This prospectus relates to the possible resale by certain of our stockholders, who we refer to in this prospectus as the “selling stockholders,” of up to 653,872 shares of our common stock, as identified in the table below.

On January 9, 2019, pursuant to three separate asset purchase agreements (the “Asset Purchase Agreements”) entered into among certain indirect wholly-owned subsidiaries of SEACOR Marine Holdings Inc. and each of McCall Marine Transportation, L.L.C., Carlene McCall, L.L.C. and N.F. McCall Offshore, L.L.C. (the “Sellers”), the Company acquired a total of three fast support vessels from the Sellers in exchange for a total of 603,872 shares of the Company’s common stock issued to affiliates of the Sellers (the “Seller Affiliates” and such shares, the “Subject Shares”). The Subject Shares were issued in a private placement transaction exempt from the registration requirements of the Securities Act under Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”). In determining that the issuance of the shares used as consideration for the purchase of the vessels qualified for an exemption under Section 4(a)(2), the Company relied on the following facts: (i) all of the Sellers and Seller Affiliates were accredited investors or qualified institutional buyers, (ii) the Company did not use any form of general solicitation or advertising to offer the common stock and (iii) the investment intent of the Sellers or any Seller Affiliates.

In connection with the Asset Purchase Agreements, we entered into a registration rights agreement with the Seller Affiliates (the “McCall Registration Rights Agreement”) and we are registering the Subject Shares in accordance with our obligations under the McCall Registration Rights Agreement.

On March 15, 2019, Seabulk Overseas Transport, Inc. (“Seabulk Overseas”), a wholly-owned subsidiary of SEACOR Marine, acquired the remaining 6.25% minority interest in Windcat Workboats Holdings Ltd. (“Windcat Workboats”) that it did not previously own upon the exercise by Roleen B.V. (the “Windcat Seller”) of a put option under a certain subscription and shareholders agreement, initially dated as of December 22, 2011, as amended. As partial consideration for the acquisition of such minority interest in Windcat Workboats, SEACOR Marine issued to an affiliate of Windcat Seller (“Windcat Seller Affiliate”) an aggregate of 50,000 shares of its common stock in a private placement in accordance with Section 4(a)(2) of the Securities Act, pursuant to the terms of a certain share purchase agreement with Windcat Seller (the “Windcat Share Purchase Agreement”). In determining that the issuance of the shares used as consideration for the acquisition of the minority interests in Windcat Workboats qualified for the exemption provided by Section 4(a)(2), the Company relied on the following facts: (i) the Windcat Seller and Windcat Seller Affiliate were accredited investors or qualified institutional buyers, (ii) the Company did not use any form of general solicitation or advertising to offer the common stock and (iii) the investment intent of the Windcat Seller or Windcat Seller Affiliate.

In connection with the Windcat Share Purchase Agreement, we entered into a registration rights agreement with the Windcat Seller Affiliate (the “Windcat Registration Rights Agreement”) and we are registering the shares in accordance with our obligations under the Windcat Registration Rights Agreement.

The following table sets forth information with respect to the maximum number of our common stock that may be offered from time to time by each selling shareholder under this prospectus. The selling stockholders identified below may currently hold or acquire at any time common stock in addition to those registered hereby. In addition, the selling stockholders identified below may sell, transfer, assign or otherwise dispose of some or all of their common stock pursuant to the safe harbor provided by Rule 144 under the Securities Act or in private placement transactions exempt from or not subject to the registration requirements of the Securities Act. Accordingly, we cannot give an estimate as to the amount of common stock that will be held by the selling stockholders upon termination of this offering. Information concerning the selling stockholders may change from time to time and, if necessary, we will supplement this prospectus accordingly.

To our knowledge, except as set forth herein, none of the selling stockholders has, or has had within the past three years, any position, office or other material relationship with us or any of our predecessors or affiliates,

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other than their ownership of our common stock. Because each selling stockholder may sell all or a portion of the common stock registered hereby, we cannot currently estimate the number or percentage of common stock that each selling stockholder will hold upon completion of the applicable offering.

None of the selling stockholders is a broker-dealer registered under Section 15 of the Exchange Act, or an affiliate of a broker-dealer registered under Section 15 of the Exchange Act.

We have prepared the table and the related notes based on information supplied to us by the selling stockholders on or prior to March 15, 2019. We have not sought to verify such information. Other information about the selling stockholders may change over time.

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PLAN OF DISTRIBUTION

Selling Stockholders’ Plan of Distribution

We are registering the common stock held by the selling stockholders to permit the selling stockholders to resell these securities from time to time after the date of this prospectus. We will not receive any proceeds from the sale by the selling stockholders of the common stock covered by this prospectus. The selling stockholders may act independently of us in making decisions with respect to the timing, manner and size of each of their sales. These sales may be effected in one or more transactions including:

If the selling stockholders effect such transactions by selling common stock to or through underwriters, broker-dealers or agents, such underwriters, broker-dealers or agents may receive commissions in the form of discounts, concessions or commissions from such selling stockholders or commissions from purchasers of the common stock for whom they may act as agent or to whom they may sell as principal (which discounts, concessions or commissions as to particular underwriters, broker-dealers or agents may be in excess of those customary in the types of transactions involved). In connection with sales of the common stock or otherwise, the selling stockholders may enter into hedging transactions with broker-dealers, which may in turn engage in short sales of the common stock in the course of hedging in positions they assume. The selling stockholders may also sell common stock short and deliver common stock covered by this prospectus to close out short positions, and to return borrowed shares in connection with such short sales, provided that the short sales are made after the registration statement of which this prospectus forms a part is declared effective. The selling stockholders may also loan or pledge common stock to broker-dealers in connection with bona fide margin accounts secured by the common stock, which shares broker-dealers could in turn sell if such selling stockholders default in the performance of their respective secured obligations.

The selling stockholders may pledge or grant a security interest in some or all of common stock beneficially owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the common stock from time to time pursuant to this prospectus. The selling stockholders also may transfer and donate the common stock in other circumstances in which case the

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transferees, donees or other successors in interest will be the selling beneficial owners for purposes of this prospectus. We will file an amendment or supplement to this prospectus, amending, if necessary, the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus.

Under the securities laws of some states, the common stock may be sold in such states only through registered or licensed brokers or dealers. In addition, in some states the common stock may not be sold unless such securities have been registered or qualified for sale in such state or an exemption from registration or qualification is available and is complied with.

There can be no assurance that the selling stockholders will sell any or all of the common stock registered pursuant to the registration statement of which this prospectus forms a part.

The selling stockholders and any other persons participating in such distribution will be subject to applicable provisions of the Securities Exchange Act of 1934, and the rules and regulations thereunder, including, without limitation, Regulation M of the Securities Exchange Act of 1934, which may limit the timing of purchases and sales of any of the common stock by the selling stockholders and any other participating persons. Regulation M may also restrict the ability of any person engaged in the distribution of the common stock to engage in market-making activities with respect to the common stock. All of the foregoing may affect the marketability of the common stock and the ability of any person or entity to engage in market-making activities with respect to the common stock.

We will pay all expenses of the registration of the common stock, however, the selling stockholders will pay all underwriting discounts and selling commissions, if any. We will indemnify the selling stockholders against liabilities, including liabilities under the Securities Act, in accordance with the Registration Rights Agreement, or the selling stockholders will be entitled to contribution in accordance with the terms of such agreements. We may be indemnified by the selling stockholders against civil liabilities, including liabilities under the Securities Act, that may arise from any written information furnished to us by the selling stockholders specifically for use in this prospectus, in accordance with the Registration Rights Agreement or, we may be entitled to contribution in accordance with the terms of such agreements.

Once sold under the registration statement of which this prospectus forms a part, the common stock held by the selling stockholders will be freely tradable by the purchasers of such securities, other than our affiliates.

To the extent required, this prospectus may be amended or supplemented from time to time to describe a specific plan of distribution. The place and time of delivery for the securities in respect of which this prospectus is delivered will be set forth in the accompanying prospectus supplements.

Any shares of common stock, covered by this prospectus that qualify for sale pursuant to Rule 144 of the Securities Act may be sold under Rule 144, rather than pursuant to this prospectus.

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LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, our counsel, Milbank LLP, New York, New York, will pass upon certain legal matters in connection with the offered securities. Any underwriters, dealers or agents will be advised about other issues relating to any offering by their own legal counsel.

EXPERTS

The consolidated financial statements as of December 31, 2018 and 2017 and for the two years ended December 31, 2018 incorporated by reference in this prospectus and elsewhere in the registration statement have been so incorporated by reference in reliance upon the report of Grant Thornton LLP, independent registered public accountants, upon the authority of said firm as experts in accounting and auditing.

The consolidated financial statements of SEACOR Marine Holdings Inc. for the year ended December 31, 2016 appearing in SEACOR Marine Holdings Inc.’s Annual Report (Form 10-K) for the year ended December 31, 2018, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their report thereon included therein, and incorporated herein by reference. Such financial statements are, and audited financial statements to be included in subsequently filed documents will be, incorporated herein in reliance upon the report of Ernst & Young LLP pertaining to such financial statements (to the extent covered by consents filed with the Securities and Exchange Commission) given on the authority of such firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may obtain copies of these reports, proxy statements and other documents at the SEC’s website, the address of which is http://www.sec.gov as well as on the Company’s website, the address of which is https://www.seacormarine.com/.

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DOCUMENTS INCORPORATED BY REFERENCE

The SEC allows us to “incorporate by reference” the information in certain documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus, and the information that we subsequently file with the SEC will automatically update and supersede this information. This prospectus incorporates by reference the Company’s documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act:

In addition, we incorporate by reference into this prospectus (i) all documents filed by us pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of this prospectus and before we have sold all of the common stock to which the prospectus relates or the offering is otherwise terminated and (ii) all documents filed by us pursuant to the Exchange Act after the date of the initial registration statement and prior to effectiveness of the registration statement.

To the extent that any information contained in any Current Report on Form 8-K, or any exhibit thereto, was furnished, rather than filed with, the SEC, that information or exhibit is specifically not incorporated by reference in this document.

You may obtain copies of these documents, other than exhibits, free of charge on our website, www.seacormarine.com, as soon as reasonably practicable after they have been filed with the SEC and through the SEC’s website, www.sec.gov. You may also obtain such documents by submitting a written request either to Investor Relations, SEACOR Marine Holdings Inc., 12121 Wickchester Lane, Suite 500, Houston, Texas 77079 or to InvestorRelations@seacormarine.com, or an oral request by calling the Company’s Investor Relations group at (346) 980-1700.

You should rely only on the information contained or incorporated by reference in this prospectus. We have not authorized anyone to provide you with information that is different from the information contained in this prospectus. This prospectus speaks only as of its date unless the information specifically indicates that another date applies.

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Common Stock

PROSPECTUS

                , 2019

Part II

Information Not Required in Prospectus

The following table sets forth the estimated fees and expenses, other than underwriting discounts and commissions, in connection with the issuance and distribution of the securities being registered hereby. With the exception of the SEC registration fee, all amounts set forth below are estimates. All of such expenses are being borne by the registrant unless otherwise indicated.

Section 145 of the DGCL provides that a corporation may indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of the fact that he is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by him in connection with such action, suit or proceeding if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe his conduct was unlawful. Section 145 further provides that a corporation similarly may indemnify any such person serving in any such capacity who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that he is or was a director, officer, employee or agent of the corporation or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorney’s fees) actually and reasonably incurred in connection with the defense or settlement of such action or suit if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the corporation and except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Delaware Court of Chancery or such other court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all of the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Delaware Court of Chancery or such other court shall deem proper.

The Company’s Bylaws authorize the indemnification of its officers and directors, consistent with Section 145 of the DGCL, as amended. The Company has entered into indemnification agreements with each of its directors and executive officers. These agreements, among other things, require us to indemnify each director and executive officer to the fullest extent permitted by Delaware law, including indemnification of expenses such as attorneys’ fees, judgments, fines and settlement amounts incurred by the director or executive officer in any action or proceeding, including any action or proceeding by or in right of us, arising out of the person’s services as a director or executive officer.

Reference is made to Section 102(b)(7) of the DGCL, which enables a corporation in its original certificate of incorporation or an amendment thereto to eliminate or limit the personal liability of a director for violations of

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the director’s fiduciary duty, except (i) for any breach of the director’s duty of loyalty to the corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) pursuant to Section 174 of the DGCL, which provides for liability of directors for unlawful payments of dividends of unlawful stock purchase or redemptions or (iv) for any transaction from which a director derived an improper personal benefit. The Company’s Certificate of Incorporation provides for such exculpation from personal liability.

The Company maintains standard policies of insurance that provide coverage (i) to its directors and officers against loss rising from claims made by reason of breach of duty or other wrongful act and (ii) to the Company with respect to indemnification payments that it may make to such directors and officers.

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Item 16. Exhibits

Item 17. Undertakings

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (i), (ii) and (iii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to

the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

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(4) That, for the purpose of determining liability under the Securities Act to any purchaser:

(i) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which the prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof; provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(5) That, for the purpose of determining liability of the registrant under the Securities Act to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(6) That, for purposes of determining any liability under the Securities Act, each filing of the Registrant’s annual report pursuant to Section 13(a) or 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(7) Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection

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(8) For purposes of determining any liability under the Securities Act, the information omitted from the form of prospectus filed as part of this Registration Statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act shall be deemed to be part of this Registration Statement as of the time it was declared effective.

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SIGNATURES

Pursuant to the requirements of the Securities Act, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement on Form S-3 to be signed on its behalf by the undersigned, thereunto duly authorized in the City of New York, State of New York, on the 1st day of April, 2019.

POWER OF ATTORNEY

Each person whose signature appears below constitutes and appoints John Gellert, Jesús Llorca, and Andrew H. Everett II and each of them, as his true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents full power and authority to do and perform each and every act and thing requisite or necessary to be done in connection therewith, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or their or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act, this registration statement has been signed by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

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Exhibit 4.2

REGISTRATION RIGHTS AGREEMENT

BY AND BETWEEN

SEACOR MARINE HOLDINGS INC.

AND

ROBBERT VAN RIJK

TABLE OF CONTENTS

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REGISTRATION RIGHTS AGREEMENT

This REGISTRATION RIGHTS AGREEMENT (this “Agreement”) is made and entered into as of March 15, 2019, by and between SEACOR Marine Holdings Inc., a Delaware corporation (the “Company”), and Robbert van Rijk, a individual resident of the Netherlands ( “Mr. Van Rijk”).

WHEREAS, this Agreement is made in connection with the issuance and sale of shares of common stock, par value $0.01 per share, of the Company (“Common Stock”) as partial consideration for the purchase of certain shares pursuant to the Share Purchase Agreement (as hereinafter defined); and

WHEREAS, the Company has agreed to provide the registration and other rights set forth in this Agreement for the benefit of Mr. Van Rijk pursuant to the Share Purchase Agreement.

NOW THEREFORE, in consideration of the mutual covenants and agreements set forth herein and for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by each party hereto, the parties hereby agree as follows:

ARTICLE I

DEFINITIONS

Section 1.01 Definitions. The terms set forth below are used herein as so defined:

“Affiliate” means, with respect to any Person, any other Person that directly or indirectly through one or more intermediaries controls, is controlled by or is under common control with, the Person in question. As used herein, the term “control” means the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through ownership of voting securities, by contract or otherwise.

“Agreement” has the meaning specified therefor in the introductory paragraph of this Agreement.

“Business Day” means any day other than a Saturday, Sunday, any federal holiday or any other day on which banking institutions in the State of New York are authorized or required to be closed by law or governmental action.

“Commission” means the U.S. Securities and Exchange Commission.

“Common Stock Price” means the volume weighted average closing price per share of the Common Stock (as reported by Bloomberg L.P. (or if not available via Bloomberg L.P. another mutually agreed upon source)) for the 10 trading days immediately preceding the date on which the determination is made.

“Common Stock” has the meaning specified therefor in the introductory paragraph of this Agreement.

“Company” has the meaning specified therefor in the introductory paragraph to this Agreement.

“Consideration Shares” means the Common Stock acquired pursuant to the Share Purchase Agreement.

“Effectiveness Deadline” has the meaning specified therefor in Section 2.02(b) of this Agreement.

“Effectiveness Period” has the meaning specified therefor in Section 2.01 of this Agreement.

“Holder” means the record holder of any Registrable Securities, which includes, as of the date of this Agreement, Mr. Van Rijk.

“Liquidated Damages” has the meaning specified therefor in Section 2.02(a) of this Agreement.

“Liquidated Damages Multiplier” means the product obtained by multiplying (x) the Common Stock Price by (y) the number of Registrable Securities held by a Holder that may not be disposed of without restriction and without the need for current public information pursuant to any section of Rule 144 (or any successor rule or regulation to Rule 144 then in force) under the Securities Act of 1933, as amended (the “Securities Act”).

“Mandatory Shelf Filing Date” has the meaning specified therefore in Section 2.01 of this Agreement.

“Mr. Van Rijk” has the meaning specified therefor in the introductory paragraph to this Agreement.

“Person” means an individual or a corporation, limited liability company, partnership, joint venture, trust, unincorporated organization, association, government agency or political subdivision thereof or other entity.

“Registrable Securities” means, except as otherwise set forth in Section 1.02, the Consideration Shares (including any type of interest issued to the Holder as a result of Section 3.04).

“Registration Expenses” has the meaning specified therefor in Section 2.06(b) of this Agreement.

“Registration Statement” has the meaning specified therefor in Section 2.01 of this Agreement.

“Selling Holder” means a Holder who is selling Registrable Securities pursuant to a registration statement.

“Share Purchase Agreement” means that certain Share Purchase Agreement, dated as of the date hereof, by and among the Company, Seabulk Overseas Transport, Inc. and Roleen B.V..

Section 1.02 Registrable Securities. Any Registrable Security will cease to be a Registrable Security (a) when a registration statement covering such Registrable Security becomes or has been declared effective by the Commission and such Registrable Security has been sold or disposed of pursuant to such effective registration statement; (b) when such Registrable Security has been disposed of pursuant to any section of Rule 144 (or any similar provision then in effect) under the Securities Act; (c) when such Registrable Security is held by the Company or one of its subsidiaries or Affiliates; (d) when such Registrable Security has been sold or disposed of in a private transaction in which the transferor’s rights under this Agreement are not assigned to the transferee of such securities pursuant to Section 2.09 hereof or (e) when such Registrable Security becomes eligible for resale without restriction and without the need for current public information pursuant to any section of Rule 144 (or any similar provision then in effect) under the Securities Act, if the Holder of such Registrable Security is not an affiliate (as defined in Rule 144(a)(1)) of the Company.

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ARTICLE II

REGISTRATION RIGHTS

Section 2.01 Mandatory Registration. No later than thirty (30) days after the date of this Agreement or such other date as may otherwise be agreed to in writing by the Company and Mr. Van Rijk (such date, the “Mandatory Shelf Filing Date”), the Company shall prepare and use its commercially reasonable efforts to file a registration statement with the Commission on Form S-3 under the Securities Act providing for registration and resale, on a continuous or delayed basis and from time to time pursuant to Rule 415 under the Securities Act, of all of the Registrable Securities then outstanding; provided, however, that if the Company is not eligible to file and use a Form S-3 to register resales by the Holders by the Mandatory Shelf Filing Date it shall prepare and use its commercially reasonable efforts to file such form of registration statement as is then available to permit resales by the Holders on a continuous or delayed basis (including a Form S-1); provided, further, that if the Company has filed the registration statement on a form other than Form S-3 and subsequently becomes eligible to use Form S-3 or any equivalent or successor form or forms, the Company may elect, in its sole discretion, to (i) file a post-effective amendment to the registration statement converting such registration statement to a registration statement on Form S-3 or any equivalent or successor form or forms or (ii) withdraw such registration statement and file a registration statement on Form S-3 or any equivalent or successor form or forms, (the registration statement on such form, as amended or supplemented, the “Registration Statement”). The Company shall use its commercially reasonable efforts to cause the Registration Statement to be declared effective under the Securities Act by the Commission as soon as reasonably practicable after the Mandatory Shelf Filing Date. The Company shall use its commercially reasonable efforts to keep the Registration Statement continuously effective under the Securities Act until the earlier of (A) the date when all of the Registrable Securities covered by such Registration Statement have been sold, and (B) the date on which all of the Consideration Shares cease to be Registrable Securities hereunder (such period, the “Effectiveness Period”). The Registration Statement when effective (including the documents incorporated therein by reference) will comply as to form in all material respects with all applicable requirements of the Securities Act and the Exchange Act and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading (in the case of any prospectus contained in such Registration Statement, in the light of the circumstances under which a statement is made). As soon as practicable following the date that the Registration Statement becomes effective, but in any event within two (2) Business Days of such date, the Company shall provide the Holders with written notice of the effectiveness of the Registration Statement.

Section 2.02 Failure to File or Become Effective; Liquidated Damages.

(a) If the Company has not filed the Registration Statement with the Commission on or prior to the applicable Mandatory Shelf Filing Date, then each Holder shall be entitled to a payment (with respect to each Registrable Security held by the Holder), as liquidated damages and not as a penalty, in an amount equal to 0.25% of the Liquidated Damages Multiplier of such Holder for the first 30-day period and (ii) an additional 0.25% of the Liquidated Damages Multiplier of such Holder with respect to each subsequent 30- day period, up to a maximum amount of 1.00% of the Liquidated Damages Multiplier of such Holder (the “Liquidated Damages”), which shall accrue daily until such date that the Company has filed the Registration Statement with the Commission. To the extent that during any 30-day period a Holder is no longer entitled to receive Liquidated Damages, the Company shall only be required to pay the Liquidated Damages that have accrued to such date.

(b) If the Registration Statement is not declared effective by the Commission on or before the earlier of (i) if the Registration Statement is subject to review by the Commission, ninety (90) days following the date on which the Company has filed its proxy statement for its 2019 Annual Meeting of Shareholders, and (ii) if the Registration Statement is not subject to review by the Commission, ten (10) days following the date of it files its proxy statement for its 2019 Annual Meeting of Shareholders (such earlier date, the “Effectiveness Deadline”), then each Holder shall be entitled to a payment (with respect to each Registrable Security held by the Holder), as liquidated damages and not as a penalty, of Liquidated Damages of such Holder, which shall accrue daily until such date that the Registration Statement is declared effective by the Commission.

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(c) The Liquidated Damages shall be paid to each Holder in cash within ten (10) Business Days following the last day of 30-day period that the Holders are entitled to such Liquidated Damages. Any payments made pursuant to this Section 2.02 shall constitute the Holders’ exclusive remedy for such events. Any Liquidated Damages due under this Section 2.02 shall be paid to the Holders in immediately available funds. The obligation to pay the Liquidated Damages to a Holder pursuant to this Section 2.02 shall cease at such time as the Registrable Securities become eligible for resale by such Holder under Rule 144 of the Securities Act without regard to any volume or manner of sale restrictions.

Section 2.03 Blackout and Delay Rights. Notwithstanding anything to the contrary contained herein:

(a) the Company shall not be required to (i) file a Registration Statement (or any amendment thereto) or, (ii) if a Registration Statement has been filed but not declared effective by the Commission, request effectiveness of such Registration Statement, for a period of up to 60 days, if the Company in its sole discretion determines (A) in good faith that a postponement is in the best interest of the Company and its stockholders generally due to a pending transaction involving the Company (including a pending securities offering by the Company, or any proposed financing, acquisition, merger, tender offer, business combination, corporate reorganization, consolidation or other significant transaction involving the Company), (B) such registration would render the Company unable to comply with applicable securities laws, (C) such registration would require disclosure of material information that the Company has a bona fide business purpose for preserving as confidential, or (D) audited financial statements as of a date other than the fiscal year end of the Company would be required to be prepared; provided, however, that in no event shall any such period exceed an aggregate of 90 days in any 365-day period; and

(b) the Company may, upon written notice to any Selling Holder whose Registrable Securities are included in the Registration Statement or other registration statement contemplated by this Agreement, suspend such Selling Holder’s use of any prospectus which is a part of the Registration Statement or other registration statement (in which event the Selling Holder shall discontinue sales of the Registrable Securities pursuant to the Registration Statement or other registration statement contemplated by this Agreement but may settle any previously made sales of Registrable Securities) if (i) the Company determines that it would be required to make disclosure of material information in the Registration Statement that the Company has a bona fide business purpose for preserving as confidential, (ii) the Company has experienced some other material non-public event the disclosure of which at such time, in the good faith judgment of the Company, would adversely affect the Company or (iii) the Company determines that it is required to amend or supplement the affected Registration Statement or the related prospectus so that such Registration Statement or prospectus does not include an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the case of the prospectus in light of the circumstances under which they were made, not misleading (an “Allowed Delay”); provided, however, in no event shall the Selling Holders be suspended from selling Registrable Securities pursuant to the Registration Statement or other registration statement for a period that exceeds an aggregate of 90 days in any 180-day period. Upon disclosure of such information or the termination of the condition described above, the Company shall provide prompt notice to the Selling Holders whose Registrable Securities are included in the Registration Statement, and shall promptly terminate any suspension of sales it has put into effect and shall take such other reasonable actions to permit registered sales of Registrable Securities as contemplated in this Agreement.

Section 2.04 Sale Procedures. In connection with its obligations under this Article II, the Company will, as expeditiously as possible:

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(a) prepare and file with the Commission such amendments and supplements to the Registration Statement and the prospectus used in connection therewith as may be necessary to keep the Registration Statement effective for the Effectiveness Period and as may be necessary to comply with the provisions of the Securities Act with respect to the disposition of all Registrable Securities covered by the Registration Statement;

(b) make available to each Selling Holder (i) as far in advance as reasonably practicable before filing the Registration Statement or any other registration statement contemplated by this Agreement or any supplement or amendment thereto, upon request, copies of reasonably complete drafts of all such documents proposed to be filed (including exhibits but excluding each document incorporated by reference), and provide each such Selling Holder the opportunity to reasonably object to any information pertaining to such Selling Holder and its plan of distribution that is contained therein and make the corrections reasonably requested by such Selling Holder with respect to such information prior to filing the Registration Statement or such other registration statement or supplement or amendment thereto, and (ii) such number of copies of the Registration Statement or such other registration statement and the prospectus included therein and any supplements and amendments thereto as such Selling Holder may reasonably request in order to facilitate the public sale or other disposition of the Registrable Securities covered by such Registration Statement or other registration statement;

(c) if applicable, use its commercially reasonable efforts to register or qualify the Registrable Securities covered by the Registration Statement or any other registration statement contemplated by this Agreement under the securities or blue sky laws of such jurisdictions as the Selling Holders shall reasonably request in writing by the time the Registration Statement is declared effective by the Commission; provided, however, that the Company will not be required to qualify generally to transact business in any jurisdiction where it is not then required to so qualify, take any action that would subject itself to general taxation in any jurisdiction where it would not otherwise be so subject or to take any action that would subject it to general service of process in any such jurisdiction where it is not then so subject;

(d) promptly notify each Selling Holder, at any time when a prospectus relating thereto is required to be delivered by any of them under the Securities Act in connection with a resale of Registrable Securities, of (i) the filing of the Registration Statement or any other registration statement contemplated by this Agreement or any prospectus or prospectus supplement to be used in connection therewith, or any amendment or supplement thereto, and, with respect to such Registration Statement or any other registration statement or any post-effective amendment thereto, when the same has become effective; and (ii) the receipt of any written or verbal comments from the Commission with respect to any filing referred to in clause (i) and any written request by the Commission for amendments or supplements to the Registration Statement or any other registration statement or any prospectus or prospectus supplement thereto;

(e) immediately notify each Selling Holder, at any time when a prospectus relating thereto is required to be delivered under the Securities Act, of (i) the happening of any event as a result of which the prospectus or prospectus supplement contained in the Registration Statement or any other registration statement contemplated by this Agreement, as then in effect, includes an untrue statement of a material fact or omits to state any material fact required to be stated therein or necessary to make the statements therein not misleading (in the case of any prospectus contained therein, in the light of the circumstances under which a statement is made); (ii) the issuance or express threat of issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or any other registration statement contemplated by this Agreement, or the initiation of any proceedings for that purpose; or (iii) the receipt by the Company of any notification with respect to the suspension of the qualification of any Registrable Securities for sale under the applicable securities or blue sky laws of any jurisdiction. Following the provision of such notice, the Company agrees to as promptly as practicable amend or supplement the prospectus or prospectus supplement or take other appropriate action so that the prospectus or prospectus supplement does not include an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading in the light of the circumstances then existing and to take such other commercially reasonable action as is necessary to remove a stop order, suspension, threat thereof or proceedings related thereto;

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(f) upon request and subject to appropriate confidentiality obligations, furnish to each Selling Holder copies of any and all transmittal letters or other correspondence with the Commission or any other governmental agency or self-regulatory body or other body having jurisdiction (including any domestic or foreign securities exchange) relating to the Registration Statement;

(g) otherwise use its commercially reasonable efforts to comply with all applicable rules and regulations of the Commission, and make available to its security holders, as soon as reasonably practicable, an earnings statement, which earnings statement shall satisfy the provisions of Section 11(a) of the Securities Act and Rule 158 promulgated thereunder;

(h) cause all such Registrable Securities registered pursuant to this Agreement to be listed on each securities exchange or nationally recognized quotation system on which similar securities issued by the Company are then listed;

(i) use its commercially reasonable efforts to cause the Registrable Securities to be registered with or approved by such other governmental agencies or authorities as may be necessary by virtue of the business and operations of the Company to enable the Selling Holders to consummate the disposition of such Registrable Securities;

(j) provide a transfer agent and registrar for all Registrable Securities covered by such registration statement not later than the effective date of such registration statement;

(k) if requested by a Selling Holder, (i) incorporate in a prospectus supplement or post-effective amendment such information as such Selling Holder reasonably requests to be included therein relating to the sale and distribution of Registrable Securities, including information with respect to the number of Registrable Securities being offered or sold, the purchase price being paid therefor, information regarding the underwriters, and any other terms of the offering of the Registrable Securities to be sold in such offering and (ii) make all required filings of such prospectus supplement or post-effective amendment after being notified of the matters to be incorporated in such prospectus supplement or post-effective amendment; and

(l) if requested by a Selling Holder, enter into a customary underwriting agreement relating to the sale and distribution of Registrable Securities.

The Company will not name a Holder as an underwriter as defined in Section 2(a)(11) of the Securities Act in any Registration Statement without such Holder’s consent. If the staff of the Commission requires the Company to name any Holder as an underwriter as defined in Section 2(a)(11) of the Securities Act, and such Holder does not consent thereto, then such Holder’s Registrable Securities shall not be included on the Registration Statement and the Company shall have no further obligations hereunder with respect to Registrable Securities held by such Holder or be required to pay any Liquidated Damages to the Holder.

Each Selling Holder, upon receipt of notice from the Company of the happening of any event of the kind described in subsection (e) of this Section 2.04 or the exercise of its rights pursuant to Section 2.03, shall forthwith discontinue offers and sales of the Registrable Securities by means of a prospectus or prospectus supplement until such Selling Holder’s receipt of the copies of the supplemented or amended prospectus contemplated by subsection (e) of this Section 2.04 or until it is advised in writing by the Company that the use of the prospectus may be resumed and has received copies of any additional or

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supplemental filings incorporated by reference in the prospectus, and, if so directed by the Company, such Selling Holder will deliver to the Company (at the Company’s expense) all copies in their possession or control, other than permanent file copies then in such Selling Holder’s possession, of the prospectus covering such Registrable Securities current at the time of receipt of such notice.

Section 2.05 Obligations of the Holders.

(a) Each Holder shall furnish in writing to the Company such information regarding itself, the Registrable Securities held by it and the intended method of disposition of the Registrable Securities held by it, as shall be reasonably required to effect the registration of such Registrable Securities and shall execute such documents in connection with such registration as the Company may reasonably request. At least ten (10) Business Days prior to the first anticipated filing date of any Registration Statement, the Company shall notify each Holder of the information the Company requires from such Holder if such Holder elects to have any of the Registrable Securities included in such Registration Statement. A Holder shall provide such information to the Company at least five (5) Business Days prior to the first anticipated filing date of such Registration Statement if such Holder elects to have any of the Registrable Securities included in such Registration Statement.

(b) Each Holder, by its acceptance of the Registrable Securities, agrees to cooperate with the Company as reasonably requested by the Company in connection with the preparation and filing of a Registration Statement hereunder, unless such Holder has notified the Company in writing of its election to exclude all of its Registrable Securities from such Registration Statement.

(c) Each Holder covenants and agrees that it will comply with the prospectus delivery requirements of the Securities Act as applicable to it or an exemption therefrom in connection with sales of Registrable Securities pursuant to any Registration Statement.

Section 2.06 Expenses.

(a) The Company will pay all reasonable Registration Expenses as determined in good faith. In addition, except as otherwise provided in Section 2.07 hereof, the Company shall not be responsible for legal fees incurred by Holders in connection with the exercise of such Holders’ rights hereunder.

(b) Certain Definitions. “Registration Expenses” means all expenses incident to the Company’s performance under or compliance with this Agreement to effect the registration of Registrable Securities on the Registration Statement pursuant to Section 2.01, and the disposition of such Registrable Securities, including, without limitation, all registration, filing, securities exchange listing and fees associated with the New York Stock Exchange, all registration, filing, qualification and other fees and expenses of complying with securities or blue sky laws, fees of the Financial Industry Regulatory Authority, fees of transfer agents and registrars, all word processing, duplicating and printing expenses, any transfer taxes and the fees and disbursements of counsel and independent public accountants for the Company, including the expenses of any special audits or “cold comfort” letters required by or incident to such performance and compliance.

Section 2.07 Indemnification.

(a) Indemnification by the Company. In the event of any registration of any securities of the Company under the Securities Act pursuant to this Agreement, the Company will, and hereby does, indemnify and hold harmless the seller of any Registrable Securities covered by such registration statement, its directors and officers, each other Person who participates in the offering or sale of such securities and each other Person, if any, who controls such seller, within the meaning of the Securities Act, against any

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losses, claims, damages or liabilities, joint or several, to which such seller or any such director or officer or controlling person may become subject, under the Securities Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions or proceedings, whether commenced or threatened, in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in any registration statement under which such securities were registered under the Securities Act, any preliminary prospectus, final prospectus or summary prospectus contained therein, or any amendment or supplement thereto (in all cases, including documents incorporated by reference), or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, and the Company will reimburse such seller and each such director, officer, and controlling person for any legal or any other expenses reasonably incurred by them in connection with investigating or defending any such loss, claim, liability, action or proceeding; provided that the Company shall not be liable in any such case to the extent that any such loss, claim, damage, liability (or action or proceeding in respect thereof) or expense arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in such registration statement, any such preliminary prospectus, final prospectus, summary prospectus, amendment or supplement in reliance upon and in conformity with information regarding such seller furnished by such seller (or any representative of such seller) to the Company in writing or electronically specifically stating that it is for use in the preparation thereof. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of such seller or any such director, officer or controlling person and shall survive the transfer of such securities by such seller.

(b) Indemnification by the Sellers. The Company may require, as a condition to including any Registrable Securities in any registration statement filed pursuant to Section 2.01 above, that the Company shall have received an undertaking satisfactory to it from the prospective seller of such securities, to indemnify and hold harmless (in the same manner and to the same extent as set forth in Section 2.07(a) above) the Company, each director of the Company, each officer of the Company and each other Person, if any, who controls the Company within the meaning of the Securities Act, with respect to any statement or alleged statement in or omission or alleged omission from such registration statement, any preliminary prospectus, final prospectus or summary prospectus contained therein, or any amendment or supplement thereto, if such statement or alleged statement or omission or alleged omission was made in reliance upon and in conformity with information regarding such seller furnished by such seller (or any representative of such seller) to the Company in writing or electronically specifically stating that it is for use in the preparation of such registration statement, preliminary prospectus, final prospectus, summary prospectus, amendment or supplement. The maximum liability of each seller for any such indemnification shall not exceed the amount of proceeds actually received by such seller from the sale of his/its Registrable Securities. Such indemnity shall remain in full force and effect, regardless of any investigation made by or on behalf of the Company or any such director, officer or controlling Person and shall survive the transfer of such securities by such seller.

(c) Notices of Claims, etc. Promptly after receipt by an indemnified party of notice of the commencement of any action or proceeding involving a claim referred to in Section 2.07(a) or (b) above, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party, give written notice to the latter of the commencement of such action; provided that the failure of any indemnified party to give notice as provided herein shall not relieve the indemnifying party of its obligations under Section 2.07(a) or (b) above, except to the extent that the indemnifying party is actually prejudiced by such failure to give notice. In case any such action is brought against an indemnified party, unless in such indemnified party’s reasonable judgment a conflict of interest between such indemnified and indemnifying parties may exist in respect of such claim, the indemnifying party shall be entitled to participate in and to assume the defense thereof, jointly with any other indemnifying party similarly notified to the extent that it may wish, with counsel reasonably satisfactory to such indemnified party, and after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the

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indemnifying party shall not be liable to such indemnified party for any legal or other expenses subsequently incurred by the latter in connection with the defense thereof. No indemnifying party shall, without the consent of the indemnified party, consent to entry of any judgment or enter into any settlement which does not include as an unconditional term thereof the giving by the claimant or plaintiff to such indemnified party of a release from all liability in respect to such claim or litigation. No indemnified party shall settle any claim for which indemnity maybe sought under this Agreement without the consent of the indemnifying party.

(d) Other Indemnification. Indemnification similar to that specified in Sections 2.07(a), (b) and (c) above (with appropriate modifications) shall be given by the Company and each seller of Registrable Securities with respect to any required registration or other qualification of securities under any Federal or state law or regulation of any governmental authority other than the Securities Act.

(e) Indemnification Payments. The indemnification required by this Section 2.07 shall be made by periodic payments of the amount thereof during the course of the investigation or defense, as and when bills are received or expense, loss, damage or liability is incurred.

Section 2.08 Rule 144 Reporting. With a view to making available the benefits of certain rules and regulations of the Commission that may permit the sale of the Registrable Securities to the public without registration, the Company agrees to use its commercially reasonable efforts to:

(a) make and keep public information regarding the Company available, as those terms are understood and defined in Rule 144 under the Securities Act, at all times from and after the date hereof;

(b) file with the Commission in a timely manner all reports and other documents required of the Company under the Securities Act and the Exchange Act at all times from and after the date hereof;

(c) furnish at the Company’s expense legal opinions or instruction letters regarding the removal of restrictive legends in connection with a sale under Rule 144; and

(d) so long as a Holder owns any Registrable Securities, furnish, unless otherwise available via EDGAR, to such Holder forthwith upon request a copy of the most recent annual or quarterly report of the Company, and such other reports and documents so filed as such Holder may reasonably request in availing itself of any rule or regulation of the Commission allowing such Holder to sell any such securities without registration.

Section 2.09 Transfer or Assignment of Registration Rights. The rights to cause the Company to register Registrable Securities granted to the Holders by the Company under this Article II may be transferred or assigned by any Holder to one or more transferees or assignees of Registrable Securities; provided, however, that (a) unless the transferee or assignee is an Affiliate of, and after such transfer or assignment continues to be an Affiliate of, such Holder, the amount of Registrable Securities transferred or assigned to such transferee or assignee shall represent at least $100,000 of Registrable Securities (based on the Common Stock Price), (b) the Company is given written notice prior to any said transfer or assignment, stating the name and address of each such transferee or assignee and identifying the securities with respect to which such registration rights are being transferred or assigned, and (c) each such transferee or assignee assumes in writing responsibility for its portion of the obligations of such Holder under this Agreement.

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ARTICLE III

MISCELLANEOUS

Section 3.01 Communications. All notices and other communications provided for or permitted hereunder shall be made in writing by electronic mail, courier service or personal delivery:

(a) if to Mr. Van Rijk:

Stommeerweg 72 ws 1

1431 EX Aalsmeer

The Netherlands

Email: rvr@windcatworkboats.com

with a copy to:

Jones Walker LLP

201 St. Charles Avenue

New Orleans, LA 70005

Attention: Britton Seal

Email: bseal@joneswalker.com

(b) if to a transferee of Mr. Van Rijk, to such Person at the address provided pursuant to Section 2.09 above; and

(c) if to the Company:

SEACOR Marine Holdings Inc.

12121 Wickchester Lane, Suite 500

Houston, Texas 77079

Attention: General Counsel

Email: aeverett@seacormarine.com

with a copy to:

Milbank, Tweed, Hadley & McCloy LLP

28 Liberty Street

New York, New York 10005-1413

Attention: David Zeltner

Email: dzeltner@milbank.com

and

Milbank, Tweed, Hadley & McCloy LLP

28 Liberty Street

New York, New York 10005-1413

Attention: Brett D. Nadritch

Email: bnadritch@milbank.com

All such notices and communications shall be deemed to have been received at the time delivered by hand, if personally delivered; when receipt acknowledged, if sent via facsimile or sent via Internet electronic mail; and when actually received, if sent by courier service or any other means.

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Section 3.02 Successor and Assigns. This Agreement shall inure to the benefit of and be binding upon the successors and permitted assigns of each of the parties, including subsequent Holders of Registrable Securities to the extent permitted herein.

Section 3.03 Assignment of Rights. All or any portion of the rights and obligations of any Holder under this Agreement may be transferred or assigned by such Holder only in accordance with Section 2.09 hereof.

Section 3.04 Recapitalization, Exchanges, Etc. Affecting the Shares. The provisions of this Agreement shall apply to the full extent set forth herein with respect to any and all shares of the Company or any successor or assign of the Company (whether by merger, consolidation, sale of assets or otherwise) that may be issued in respect of, in exchange for or in substitution of, the Registrable Securities, and shall be appropriately adjusted for combinations, share splits, recapitalizations, pro rata distributions of shares and the like occurring after the date of this Agreement.

Section 3.05 Aggregation of Registrable Securities. All Registrable Securities held or acquired by Persons who are Affiliates of one another shall be aggregated together for the purpose of determining the availability of any rights and applicability of any obligations under this Agreement.

Section 3.06 Specific Performance. Damages in the event of breach of this Agreement by a party hereto may be difficult, if not impossible, to ascertain, and it is therefore agreed that each such Person, in addition to and without limiting any other remedy or right it may have, will have the right to an injunction or other equitable relief in any court of competent jurisdiction, enjoining any such breach, and enforcing specifically the terms and provisions hereof, and each of the parties hereto hereby waives any and all defenses it may have on the ground of lack of jurisdiction or competence of the court to grant such an injunction or other equitable relief. The existence of this right will not preclude any such Person from pursuing any other rights and remedies at law or in equity that such Person may have.

Section 3.07 Counterparts. This Agreement may be executed in any number of counterparts and by different parties hereto in separate counterparts, each of which counterparts, when so executed and delivered, shall be deemed to be an original and all of which counterparts, taken together, shall constitute but one and the same Agreement.

Section 3.08 Headings. The headings in this Agreement are for convenience of reference only and shall not limit or otherwise affect the meaning hereof.

Section 3.09 Governing Law. THIS AGREEMENT, AND ALL CLAIMS OR CAUSES OF ACTION (WHETHER IN CONTRACT OR TORT) THAT MAY BE BASED UPON, ARISE OUT OF OR RELATE TO THIS AGREEMENT OR THE NEGOTIATION, EXECUTION OR PERFORMANCE OF THIS AGREEMENT (INCLUDING ANY CLAIM OR CAUSE OF ACTION BASED UPON, ARISING OUT OF OR RELATED TO ANY REPRESENTATION OR WARRANTY MADE IN OR IN CONNECTION WITH THIS AGREEMENT), WILL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAWS THAT WOULD REQUIRE THE APPLICATION OF THE LAWS OF ANY OTHER JURISDICTION. ANY ACTION AGAINST ANY PARTY RELATING TO THE FOREGOING SHALL BE BROUGHT IN ANY FEDERAL OR STATE COURT OF COMPETENT JURISDICTION LOCATED WITHIN THE STATE OF NEW YORK, AND THE PARTIES HERETO HEREBY IRREVOCABLY SUBMIT TO THE NON-EXCLUSIVE JURISDICTION OF ANY FEDERAL OR STATE COURT LOCATED WITHIN THE STATE OF NEW YORK OVER ANY SUCH ACTION. THE PARTIES HEREBY IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED

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BY APPLICABLE LAW, ANY OBJECTION THAT THEY MAY NOW OR HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY SUCH DISPUTE BROUGHT IN SUCH COURT OR ANY DEFENSE OF INCONVENIENT FORUM FOR THE MAINTENANCE OF SUCH DISPUTE. EACH OF THE PARTIES HERETO AGREES THAT A JUDGMENT IN ANY SUCH DISPUTE MAY BE ENFORCED IN OTHER JURISDICTIONS BY SUIT ON THE JUDGMENT OR IN ANY OTHER MANNER PROVIDED BY LAW.

Section 3.10 Severability of Provisions. Any provision of this Agreement which is prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such prohibition or unenforceability without invalidating the remaining provisions hereof or affecting or impairing the validity or enforceability of such provision in any other jurisdiction.

Section 3.11 Entire Agreement. This Agreement is intended by the parties as a final expression of their agreement and intended to be a complete and exclusive statement of the agreement and understanding of the parties hereto in respect of the subject matter contained herein. There are no restrictions, promises, warranties or undertakings, other than those set forth or referred to herein with respect to the rights granted by the Company set forth herein. This Agreement supersedes all prior agreements and understandings between the parties with respect to such subject matter.

Section 3.12 Amendment. This Agreement may be amended only by means of a written amendment signed by the Company and the Holders of a majority of the then outstanding Registrable Securities; provided, however, that no such amendment shall materially and adversely affect the rights of any Holder hereunder without the consent of such Holder.

Section 3.13 No Presumption. If any claim is made by a party relating to any conflict, omission or ambiguity in this Agreement, no presumption or burden of proof or persuasion shall be implied by virtue of the fact that this Agreement was prepared by or at the request of a particular party or its counsel.

Section 3.14 Obligations Limited to Parties to Agreement. Each of the Parties hereto covenants, agrees and acknowledges that no Person other than the Holders and the Company shall have any obligation hereunder and that, notwithstanding that one or more of the Holders may be a corporation, partnership or limited liability company, no recourse under this Agreement or under any documents or instruments delivered in connection herewith or therewith shall be had against any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the Holders or any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the foregoing, whether by the enforcement of any assessment or by any legal or equitable proceeding, or by virtue of any applicable Law, it being expressly agreed and acknowledged that no personal liability whatsoever shall attach to, be imposed on or otherwise be incurred by any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the Holders or any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the foregoing, as such, for any obligations of the Holders under this Agreement or any documents or instruments delivered in connection herewith or therewith or for any claim based on, in respect of or by reason of such obligation or its creation, except in each case for any transferee or assignee of a Holder hereunder.

Section 3.15 Independent Nature of Holder’s Obligations. The obligations of each Holder under this Agreement are several and not joint with the obligations of any other Holder, and no Holder shall be responsible in any way for the performance of the obligations of any other Holder under this Agreement. Nothing contained herein, and no action taken by any Holder pursuant thereto, shall be deemed to constitute the Holders as a partnership, an association, a joint venture or any other kind of group or entity, or create a

12

presumption that the Holders are in any way acting in concert or as a group with respect to such obligations or the transactions contemplated by this Agreement. Each Holder shall be entitled to independently protect and enforce its rights, including without limitation, the rights arising out of this Agreement, and it shall not be necessary for any other Holder to be joined as an additional party in any proceeding for such purpose.

Section 3.16 Interpretation. Article and Section references are to this Agreement, unless otherwise specified. All references to instruments, documents, contracts and agreements are references to such instruments, documents, contracts and agreements as the same may be amended, supplemented and otherwise modified from time to time, unless otherwise specified. The word “including” shall mean “including but not limited to.” Whenever any determination, consent or approval is to be made or given by a Seller under this Agreement, such action shall be in such Seller’s sole discretion unless otherwise specified.

[Signature pages to follow]

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IN WITNESS WHEREOF, the parties hereto execute this Agreement, effective as of the date first above written.

[Signature Page to Registration Rights Agreement]

Robbert van Rijk

/s/ Robbert van Rijk

[Signature Page to Registration Rights Agreement]

Exhibit 5.1

SEACOR Marine Holdings Inc.

12121 Wickchester Lane, Suite 500

Houston, TX 77079

Registration Statement on Form S-3

Ladies and Gentlemen:

This opinion is furnished to you in connection with a Registration Statement on Form S-3 (such registration statement, as amended or supplemented, is hereinafter referred to as the “Registration Statement”) filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), for SEACOR Marine Holdings Inc., a Delaware corporation (the “Company”). The Registration Statement registers for resale 653,872 shares of the Company’s common stock, par value $0.01 per share (the “Common Stock”) that were issued in connection with either (i) the asset purchase agreements, dated January 9, 2019, by and among the Company, certain indirect wholly-owned subsidiaries of SEACOR Marine Holdings Inc. and each of McCall Marine Transportation, L.L.C., Carlene McCall, L.L.C. and N.F. McCall Offshore, L.L.C. (collectively, the “Asset Purchase Agreements”) or (ii) the share purchase agreement dated March 15, 2019, by and among the Company, Seabulk Overseas Transport, Inc., a Marshall Islands corporation and wholly-owned subsidiary of the Company, Roleen B.V., a private company with limited liability organized under the laws of the Netherlands and Robbert van Rijk (the “Share Purchase Agreement”).

We are acting as counsel for the Company in connection with the registration of the Common Stock. We have examined the General Corporation Law of the State of Delaware (the “DGCL”), the Company’s Second Amended and Restated Certificate of Incorporation, as amended to the date hereof, the Company’s Second Amended and Restated Bylaws, as amended to the date hereof, the Registration Statement, the Asset Purchase Agreements, the Registration Rights Agreements and the Share Purchase Agreements. We have also examined such other Company records, including resolutions of the Company’s board of directors, certificates, agreements and other documents, and such questions of law, as we have considered necessary or appropriate for the purposes of this opinion. In our examination, we have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of all documents submitted to us as originals and the conformity with authentic original documents of all documents submitted to us as copies. As to various questions of fact material to our opinions expressed herein, we have, when relevant facts were not independently established, relied upon and assumed the accuracy and completion of certificates of the selling stockholders named in the Registration Statement and oral and written statements and representations of officers and representatives of the Company and public officials and statements and representations contained in the Registration Statement and other documents as we have deemed necessary as a basis for such opinions.

Based on and subject to the foregoing and assuming that (i) the Registration Statement and any amendments thereto (including any post-effective amendments) will have become effective and comply with all applicable laws and no stop order suspending the Registration Statement’s effectiveness will have been issued and remain in effect, in each case, at the time the Securities are offered or issued as contemplated by the Registration Statement, (ii) if required by applicable law or other regulations, a prospectus supplement will have been prepared and filed with the Commission describing the Securities offered thereby and any such prospectus supplement will at all relevant times comply with all

applicable laws, (iii) the Company has timely filed all necessary reports pursuant to the Securities Exchange Act of 1934, as amended, which are incorporated into the Registration Statement by reference and (iv) all Securities will be sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the prospectus, if required by applicable law or regulations, we advise you that in our opinion the Common Stock has been duly authorized and is validly issued, fully paid and non-assessable.

The opinions above are subject to the issuance of any legally required consents, approvals, authorizations or orders of the Commission and any other regulatory authority. We express no opinion herein as to the laws of any state or jurisdiction other than the DGCL and the federal laws of the United States of America.

This opinion is based upon currently existing statutes, rules, regulations and judicial decisions, and we disclaim any obligation to advise you of any change in any of these sources of law or subsequent legal or factual developments which might affect any matters or opinions set forth herein.

We hereby consent to the filing of this opinion with the Commission as an exhibit to the Registration Statement in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act and to the use of our name therein and in the related prospectus under the caption “Legal Matters.” In giving such consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission.

Very truly yours,

/s/ Milbank LLP

3/29/2019

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption “Experts” in the Registration Statement (Form S-3) and related Prospectus of SEACOR Marine Holdings Inc. for the registration of 653,872 shares of common stock and to the incorporation by reference therein of our report dated April, 27, 2017, with respect to the consolidated financial statements and schedule of SEACOR Marine Holdings Inc. for the year ended December 31, 2016 included in its Annual Report (Form 10-K) for the year ended December 31, 2018, filed with the Securities and Exchange Commission.

Exhibit 23.2

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We have issued our report dated March 11, 2019 with respect to the consolidated financial statements of SEACOR Marine Holdings Inc. included in the Annual Report on Form 10-K for the year ended December 31, 2018, which is incorporated by reference in this Registration Statement. We consent to the incorporation by reference of the aforementioned report in this Registration Statement, and to the use of our name as it appears under the caption “Experts.”