NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, IN WHOLE OR IN PART, DIRECTLY OR
INDIRECTLY, IN OR INTO THE UNITED STATES, AUSTRALIA, CANADA OR JAPAN, OR ANY
OTHER JURISDICTION IN WHICH THE RELEASE, PUBLICATION OR DISTRIBUTION WOULD BE
UNLAWFUL. THIS ANNOUNCEMENT DOES NOT CONSTITUTE AN OFFER OF ANY OF THE
SECURITIES DESCRIBED HEREIN.

ATHENS, GREECE, 18 November 2025 - Okeanis Eco Tankers Corp. (together with its
subsidiaries, unless context otherwise dictates, "OET" or the "Company") (NYSE:
ECO, OSE: OET) today announces a contemplated acquisition of two Suezmax tanker
newbuilding resales (the "Vessel Acquisitions"),  and a contemplated offering of
new common shares (the "Offering").

The completion of the Vessel Acquisitions are subject to completion of the
Offering, as further described below.

The Vessel Acquisitions

The Company has entered into two memoranda of agreement, whereby the Company,
pursuant to each individual memorandum of agreement, has agreed to purchase one
newbuilding Suezmax vessel (with an estimated approximate deadweight tonnage of
157,000), 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. Each vessel is expected to be delivered from the
shipyard in January 2026.  

Each of the Vessel Acquisitions is contingent on, among other things, the
Company raising sufficient capital to fund a portion of the purchase price
through the Offering, but the purchase of one vessel is not contingent on the
purchase of the other.

The Offering

In connection with the Vessel Acquisitions, the Company is contemplating an
offering of new common shares (the "Offer Shares") to raise gross proceeds of
approximately USD 100 million.
 
The subscription price for the Offer Shares and the total number of Offer Shares
will be determined by the Board of Directors of the Company (the "Board") based
on an accelerated bookbuilding process.

The net proceeds from the Offering are expected to be used to partly finance the
consideration to the sellers in the Vessel Acquisitions. However, if one or both
of the Vessel Acquisitions does not consummate, the net proceeds from the
Offering may be used for general corporate purposes.

The bookbuilding period for the Offering will commence today, 18 November 2025
at 22:00 CET and is expected to close on 19 November 2025 at 11:00 CET. The
Company reserves the right to at any time and in its sole discretion resolve to
close or to extend the application period or to cancel the Offering in part or
in whole. To facilitate an efficient bookbuilding process, a trading halt will
be imposed on the Company's shares that are trading on Euronext Oslo Børs
throughout the bookbuilding period and until final results have been announced,
expected no later than 13:00 CET on 19 November 2025. 

The minimum application and allocation amount has been set to the USD equivalent
of EUR 100,000. The Board may however, at its sole discretion, allocate Offer
Shares for amounts below the USD equivalent of EUR 100,000 to the extent
exemptions from the prospectus requirement in accordance with applicable
regulations, including the Norwegian Securities Trading Act and ancillary
regulations, are available.
 
Completion of the Offering by settlement of Offer Shares in the Depository Trust
Company (DTC) to investors in the Offering is subject to, among other things,
(i) all corporate resolutions of the Company required to complete the Offering
being validly made, including without limitation, the Board or a committee
thereof approving the allocation and issuance of Offer Shares