SMHI SEACOR Marine Holdings Inc

Filed pursuant to Rule 424(b)(5)
Registration No. 333-284783

PROSPECTUS

$200,000,000

SEACOR MARINE HOLDINGS INC.

Common Stock

Preferred Stock

Warrants

Units

We may, from time to time, offer and sell up to $200,000,000 of any combination of our common stock, preferred stock, or warrants described in this prospectus, either individually or in combination with other securities, at prices and on terms described in one or more supplements to this prospectus. We may also offer common stock upon conversion of preferred stock, or common stock or preferred stock upon the exercise of warrants. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings.

Each time we offer securities, to the extent applicable, we will provide the specific terms of the securities offered in one or more supplements to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. Any such prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before buying any of the securities being offered.

The securities offered by this prospectus may be sold directly to investors, through agents designated from time to time or to or through underwriters or dealers. We will set forth the names of any underwriters or agents and any applicable fees, commissions, discounts and over-allotments in an accompanying prospectus supplement. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus and in the applicable prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

Our common stock is traded on the New York Stock Exchange (“NYSE”) under the symbol “SMHI.” On February 19, 2025, the last reported sale price of a share of our common stock on the NYSE was $6.81. The applicable prospectus supplement will contain information, where applicable, as to any other listing, if any, on the NYSE or any securities market or other exchange of the securities covered by the applicable prospectus supplement.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties referenced under the heading “risk factors“ on page 6 of this prospectus as well as those contained in the applicable prospectus supplement (if any) and any related free writing prospectus, and in the documents that are incorporated by reference into this prospectus.

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

The date of this prospectus is February 24, 2025

TABLE OF CONTENTS

i

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or the SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may offer shares of our common stock, preferred stock, and/or warrants to purchase our common stock or preferred stock, either individually or in units, in one or more offerings, up to a total dollar amount of $200,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, to the extent required, we will provide a prospectus supplement that will contain more specific 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) 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 and any related free writing prospectus, together with the information incorporated herein by reference as described under the headings “Where You Can Find Additional Information” and “Incorporation of Certain Information by Reference” before buying any of the securities being offered. We 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 different 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 Additional Information.”

1

2

3

4

5

RISK FACTORS

An investment in our securities involves a certain degree of risk. You should carefully consider the factors contained in our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 under the heading “Risk Factors” and updated, if applicable, in our Quarterly Reports on Form 10-Q before investing in our securities. You should also consider similar information contained in any Annual Report on Form 10-K, Quarterly Report on Form 10-Q or other document filed by us with the SEC after the date of this prospectus before deciding to invest in our securities. If any of these risks were to occur, our business, financial condition or results of operations could be adversely affected. In that case, the trading price of our common stock or other securities could decline and you could lose all or part of your investment. When we offer and sell any securities pursuant to a prospectus supplement, we may include additional risk factors relevant to such securities in the prospectus supplement.

6

FORWARD-LOOKING STATEMENTS

This prospectus, the documents incorporated by reference herein contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or 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 related to forward-looking statements include, but are not necessarily limited to, those relating to:

7

8

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 “Incorporation of Certain Information by Reference,” all of which are accessible on the SEC’s website at www.sec.gov.

9

USE OF PROCEEDS

We will retain broad discretion over the use of the net proceeds from the sale of the securities offered by us hereby. Except as described in any prospectus supplement or any related free writing prospectus that we may authorize to be provided to you, we currently intend to use the net proceeds from the sale of the securities offered by us hereby for general corporate purposes, which may include capital expenditures, working capital and general and administrative expenses. We will set forth in the applicable prospectus supplement or free writing prospectus our intended use for the net proceeds received from the sale of any securities sold pursuant to the prospectus supplement or free writing prospectus. Pending these uses, we intend to invest the net proceeds in U.S. government or agency obligations, commercial paper, money market accounts, short-term marketable securities, bank deposits or certificates of deposit, repurchase agreements collateralized by U.S. government or agency obligations or other short-term investments.

10

DETERMINATION OF OFFERING PRICE

We will offer the securities in amounts, at prices and on terms to be determined by market conditions at the time of the offerings.

11

PLAN OF DISTRIBUTION

SEACOR Marine’s Plan of Distribution

We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents or directly to one or more purchasers. The securities may be distributed from time to time in one or more transactions:

Each time we offer and sell securities hereto, to the extent applicable, we will provide a prospectus supplement that will set forth the terms of the offering of the securities, including:

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment option. Any public offering price and any discounts or concessions allowed or re-allowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. The prospectus supplement, naming the underwriter, will describe the nature of any such relationship.

We may sell securities directly or through agents we or they designate from time to time. The prospectus supplement will name any agent involved in the offering and sale of securities and any commissions we will pay to them. Unless the prospectus supplement states otherwise, any agent will be acting on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain purchasers to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. The prospectus supplement will set forth the conditions to these contracts and any commissions we must pay for solicitation of these contracts.

We may provide agents and underwriters with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

12

Any securities we may offer, other than our common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in over-allotment, stabilizing transactions, short-covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Over-allotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum price. Syndicate-covering or other short-covering transactions involve purchases of the securities, either through exercise of the over-allotment option or in the open market after the distribution is completed, to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

Any underwriters that are qualified market makers on the NYSE may engage in passive market making transactions in the common stock on the NYSE in accordance with Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the common stock. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

13

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 Additional Information” and “Incorporation of Certain Information by Reference.”

Common Stock

As of January 31, 2025, there were 27,669,361 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 the date of this prospectus, there were no shares of our preferred stock outstanding.

14

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.

Our board of directors will fix the designations, preferences and rights of each series, as well as the qualifications, limitations or restrictions thereof, of the preferred stock of each series that we offer under this prospectus and applicable prospectus supplements in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of that series of preferred stock. This description will include:

15

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.

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

16

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 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.

17

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 Equiniti Trust Company, LLC, 48 Wall Street, New York, NY 10005.

18

DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of common stock or preferred stock in one or more series. We may issue warrants independently or together with common stock or preferred stock, if applicable, and such warrants may be attached to or separate from our common stock or preferred stock, as applicable. While the terms summarized below will apply generally to any warrants that we may offer, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The terms of any warrants offered under a prospectus supplement may differ from the terms described below.

We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant agreement, including a form of warrant certificate, that describes the terms of the particular series of warrants we are offering before the issuance of the related series of warrants. The following summaries of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to the particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete warrant agreements and warrant certificates that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including:

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including the right to receive dividends, if any, or payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

19

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement subject to Jones Act restrictions and the Company’s Certificate of Incorporation and Bylaws. After the close of business on the expiration date, unexercised warrants will become void.

Holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information and paying any required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent.

Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining number of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements will be governed by and construed in accordance with the laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

20

DESCRIPTION OF UNITS

We may issue, in one or more series, units consisting of common stock, preferred stock and/or warrants for the purchase of common stock or preferred stock in any combination. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The units may be issued under unit agreements to be entered into between us and a unit agent, as detailed in the prospectus supplement relating to the units being offered. The prospectus supplement will describe:

While the terms summarized above will apply generally to any units that we may offer, we will describe the particular terms of any series of units in more detail in the applicable prospectus supplement. The terms of any units offered under a prospectus supplement may differ from the terms described above. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, any form of unit agreement, including any related agreements or certificates, that describes the terms of the particular series of units we are offering before the issuance of the related series of units. The material provisions of the units and any unit agreements are subject to, and qualified in their entirety by reference to, all the provisions of the unit agreement and related agreements and certificates applicable to the particular series of units that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the particular series of units that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete unit agreements and related agreements and certificates that contain the terms of the units.

21

LEGAL MATTERS

The validity of the securities being offered by this prospectus will be passed upon by Milbank LLP, New York, New York. Additional legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

22

EXPERTS

The audited financial statements incorporated by reference in this prospectus and elsewhere in the registration statement have been so incorporated by reference in reliance upon the reports of Grant Thornton LLP, independent registered public accountants, upon the authority of said firm as experts in accounting and auditing.

23

WHERE YOU CAN FIND ADDITIONAL INFORMATION

This prospectus is part of a registration statement that we have filed with the SEC. Certain information in the registration statement has been omitted from this prospectus in accordance with the rules of the SEC. We are a public company and file proxy statements, annual, quarterly and special reports and other information with the SEC. The SEC maintains a website at http://www.sec.gov that contains reports, proxy and information statements and other information regarding us and other issuers that file electronically with the SEC. We have also filed exhibits and schedules with the registration statement that are excluded from this prospectus, and you should refer to the applicable exhibit or schedule for a complete description of any statement referring to any contract or other document. You may access the registration statement of which this prospectus forms a part by visiting http://www.sec.gov.

We also maintain a website at https://seacormarine.com, through which you can access the Company’s SEC filings free of charge. The information set forth on our website is not part of this prospectus. The reference to our website address does not constitute incorporation by reference of the information contained on our website.

24

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

We are incorporating by reference in this prospectus the documents that we file with the SEC. This means that we are disclosing important information to you by referring to these filings. The information we incorporate by reference is considered a part of this prospectus, and subsequent information that we file with the SEC will automatically update and supersede this information.

Any statement contained in a document incorporated or considered to be incorporated by reference in this prospectus shall be considered to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or in any other subsequently filed document that is considered to be incorporated by reference in this prospectus modifies or supersedes such statement.

We incorporate by reference the following documents that we have filed with the SEC:

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.

You may access our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to any of these reports, free of charge on the SEC’s website. You may also access the documents incorporated by reference on our website at www.seacormarine.com. Other than the foregoing documents incorporated by reference, the information contained in, or that can be accessed through, our website is not part of this prospectus.

We will provide without charge to each person, including any beneficial owner, to whom a copy of this prospectus is delivered, upon written or oral request, a copy of any or all of the information that has been incorporated in this prospectus by reference but not delivered with this prospectus. You may 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.

25

$200,000,000

SEACOR MARINE HOLDINGS INC.

Common Stock

Preferred Stock

Warrants

Units

PROSPECTUS

February 24, 2025