IMPP

Filed Pursuant to Rule 424(b)(3)

Registration No. 333-264675

PROSPECTUS SUPPLEMENT NO. 15

(TO PROSPECTUS DATED May 16, 2022)

IMPERIAL PETROLEUM INC.

This is a supplement (“Prospectus Supplement”) to the prospectus, dated May 16, 2022 (“Prospectus”) of Imperial Petroleum Inc. (the “Company”), which forms a part of the Company’s Registration Statement on Form F-1 (Registration No. 333-264675), as amended or supplemented from time to time.

On December 16, 2022, the Company furnished a Report on Form 6-K (the “Form 6-K”) to the U.S. Securities and Exchange Commission (the “Commission”) as set forth below.

This Prospectus Supplement should be read in conjunction with, and delivered with, the Prospectus and is qualified by reference to the Prospectus except to the extent that the information in this Prospectus Supplement supersedes the information contained in the Prospectus. This Prospectus Supplement is not complete without, and may not be delivered or utilized except in connection with, the Prospectus, including any amendments or supplements to it.

Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 18 of the Prospectus for a discussion of information that should be considered in connection with an investment in our securities.

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 supplement is December 16, 2022.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of December 2022

Commission File Number 001-41095

IMPERIAL PETROLEUM INC.

(Translation of registrant’s name into English)

331 Kifissias Avenue Erithrea 14561 Athens, Greece

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F  ☒            Form 40-F  ☐

INFORMATION CONTAINED IN THIS FORM 6-K REPORT

The press release issued by Imperial Petroleum Inc. on December 16, 2022, announcing the declaration of a dividend on its 8.75% Series A Cumulative Redeemable Perpetual Preferred Stock, is attached hereto as Exhibit 99.1.

EXHIBIT INDEX

*****

This report on Form 6-K is hereby incorporated by reference into the Company’s Registration Statement on Form F-3 (Reg. No. 333-268663) filed with the SEC on December 2, 2022, including the prospectuses contained therein.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: December 16, 2022

Exhibit 99.1

IMPERIAL PETROLEUM INC.

IMPERIAL PETROLEUM INC. DECLARES DIVIDEND ON SERIES A PREFERRED SHARES

Athens, Greece, December 16, 2022 –Imperial Petroleum Inc. (Nasdaq: IMPP) (the “Company”), a ship-owning company providing petroleum products, crude oil, and drybulk seaborne transportation services, today announced a dividend of approximately $0.546875 per share on its 8.75% Series A Cumulative Redeemable Perpetual Preferred Stock (the “Series A Preferred Shares”), payable on December 30, 2022 to holders of record as of December 27, 2022. The dividend payment relates to the period from the last dividend payment date for the Series A Preferred Shares on September 30, 2022 through December 29, 2022.

There are 795,878 Series A Preferred Shares outstanding as of the date hereof. The Series A Preferred Shares trade on the Nasdaq Capital Market under the ticker symbol “IMPPP”.

ABOUT IMPERIAL PETROLEUM INC.

Imperial Petroleum Inc. is a ship-owning company providing petroleum products, crude oil and drybulk seaborne transportation services. The Company owns a total of 10 vessels; five M.R. product tankers, one Aframax oil tanker, two suezmax tankers and two handysize dry bulk carriers, with a capacity of approximately 737,000 deadweight tons (dwt). Imperial Petroleum Inc.’s shares of common stock and 8.75% Series A Cumulative Redeemable Perpetual Preferred Stock are listed on the Nasdaq Capital Market and trade under the symbols “IMPP” and “IMPPP”, respectively.

Forward-Looking Statements

Matters discussed in this release may constitute forward-looking statements. Forward-looking statements reflect our current views with respect to future events and financial performance and may include statements concerning plans, objectives, goals, strategies, future events or performance, or impact or duration of the COVID-19 pandemic and underlying assumptions and other statements, which are other than statements of historical facts. The forward-looking statements in this release are based upon various assumptions, many of which are based, in turn, upon further assumptions, including without limitation, management’s examination of historical operating trends, data contained in our records and other data available from third parties. Although IMPERIAL PETROLEUM INC. believes that these assumptions were reasonable when made, because these assumptions are inherently subject to significant uncertainties and contingencies which are difficult or impossible to predict and are beyond our control, IMPERIAL PETROLEUM INC. cannot assure you that it will achieve or accomplish these expectations, beliefs or projections. Important factors that, in our view, could cause actual results to differ materially from those discussed in the forward-looking statements include risks discussed in our filings with

the SEC and the following: the impact of the COVID-19 pandemic and efforts throughout the world to contain its spread, the strength of world economies and currencies, general market conditions, including changes in charter hire rates and vessel values, charter counterparty performance, changes in demand that may affect attitudes of time charterers to scheduled and unscheduled drydockings, shipyard performance, changes in IMPERIAL PETROLEUM INC’s operating expenses, including bunker prices, drydocking and insurance costs, ability to obtain financing and comply with covenants in our financing arrangements, or actions taken by regulatory authorities, potential liability from pending or future litigation, domestic and international political conditions, the conflict in Ukraine and related sanctions, potential disruption of shipping routes due to accidents and political events or acts by terrorists.

Risks and uncertainties are further described in reports filed by IMPERIAL PETROLEUM INC. with the U.S. Securities and Exchange Commission.

Company Contact:

Fenia Sakellaris

IMPERIAL PETROLEUM INC.

00-30-210-6250-001