Okeanis Eco Tankers Corp. - Completion and pricing of USD 115 million offering of new common shares

Athens, Greece - 19 November 2025

Okeanis Eco Tankers Corp. (the "Company" or "OET") (NYSE: ECO, OSE: OET) is pleased to announce that following strong demand it has successfully priced an offering of 3,239,436 new shares of the Company's common stock, par value USD 0.001 per share (the "Offer Shares"), at a price of USD 35.50 per Offer Share, raising gross proceeds of USD 114,999,978 (the "Offering").

The net proceeds from the Offering are expected to be used as partial consideration for the acquisition of two newbuilding Suezmax vessels (the "Vessel Acquisitions"), each currently under construction at Daehan Shipbuilding Co., Ltd., a South Korean shipyard, each from an unrelated third-party seller, for an acquisition price of USD 97 million per vessel. Each vessel is expected to be delivered from the shipyard in January 2026, subject to satisfaction of closing conditions for such delivery. If one or both of the Vessel Acquisitions do not consummate, the net proceeds from the Offering may be used for general corporate purposes.

The Offering is expected to be completed by delivery of the allocated Offer Shares to investors through the Depository Trust Company (DTC) on a delivery vs payment basis on or about 21 November 2025, subject to the satisfaction of customary closing conditions, including that the agreements for the Vessel Acquisitions remaining in full force and effect at the time of closing. The Offer Shares will be available for trading on New York Stock Exchange once the Offer Shares have been issued and settlement has taken place, expected on or about 21 November 2025.

The Company has considered the Offering in light of the equal treatment obligations under the Norwegian Securities Trading Act section 5-14, and the Board is of the opinion that the Offering is in compliance with these requirements.

The Offering is being made pursuant to the Company's shelf registration statement on Form F-3 (File No. 333-287032), which was declared effective by the U.S. Securities and Exchange Commission (the "SEC") on 21 May 2025. The Offering is being made only by means of a prospectus supplement prepared specifically in relation to the Offering, which was filed with the SEC under Rule 424(b) under the U.S Securities Act of 1933 and can be obtained at www.sec.gov. Electronic copies of the prospectus supplement and related prospectus may also be obtained by contacting Fearnley Securities AS at prospectus@fearnleys.com or Clarksons Securities AS at compliance.oslo@clarksons.com. A final prospectus supplement is expected to filed with the SEC and made available at www.sec.gov.

This announcement is for information purposes only and does not constitute or form part of an offer to sell or the solicitation of an offer to purchase or subscribe for securities, nor will there be any sale of the securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such jurisdiction. Any offers, solicitations or offers to buy, or any sales of securities will be made in accordance with the registration requirements of the Securities Act of 1933, as amended.

Advisors
Fearnley Securities AS is acting as global coordinator and joint bookrunner, and Clarksons Securities AS is acting as joint bookrunner, for the Offering (collectively referred to as the "Managers"). Fearnley Securities AS is not a U.S. registered broker-dealer, and to the extent that this offering is made within the United States, its activities will be effected only to the extent permitted by Rule 15a-6 of the Securities Exchange Act of 1934, as amended or through its affiliate Fearnley Securities Inc. Clarksons Securities AS is not a U.S. registered broker-dealer and to the extent that this offering is made within the United States, its activities will be effected only to the extent permitted by Rule 15a-6 of the Securities Exchange Act of 1934, as amended or through its affiliate Clarksons Securities, Inc.

This information is considered to be inside information pursuant to article 7 of the EU Market Abuse Regulation and is subject to the disclosure requirements pursuant to article 17 of the EU Market Abuse Regulation and section 5-12 the Norwegian Securities Trading Act. This stock exchange release was published on the Oslo Stock Exchange by Irene Chaidemenou, Legal Counsel, Okeanis Eco Tankers Corp., on the date and time provided.

About OET
OET is a leading international tanker company providing seaborne transportation of crude oil and refined products. The Company was incorporated on April 30, 2018 under the laws of the Republic of the Marshall Islands and is listed on Oslo Stock Exchange under the symbol OET and the New York Stock Exchange under the symbol ECO. The sailing fleet consists of six modern scrubber-fitted Suezmax tankers and eight modern scrubber-fitted VLCC tankers.

Okeanis Eco Tankers Corp. press release