Tullow Oil plc

Tullow publishes reserves report as of 30 June 2025

26 September 2025 Ð Tullow Oil plc (Tullow) has published its mid-year 2025 reserves report. Reserves estimates for Ghana have been extracted from a reserves report (dated 26 September 2025) prepared by the appointed external auditor, TRACS International Limited, based on data available to the end of June 2025. Reserves estimates for C™te d'Ivoire are based on the Reserves Report prepared by TRACS as of 31 December 2024, adjusted for 1H 2025 production.

Total reserves of 113.8 mmboe as of 30 June 2025 compare with total reserves of 128.5 mmboe as of 31 December 2024, both excluding Gabon. The reduction reflects 7.4 mmboe of production and revisions associated with production performance during 1H 2025 of 7.3 mmboe (Jubilee 6.3 mmboe and TEN 1.0 mmboe).

Following the Memorandum of Understanding with the Government of Ghana to extend the production licences to 2040, TRACS has estimated that 14.7 mmboe of Jubilee Contingent Resources and 3.5 mmboe of TEN Contingent Resources would move to 2P Reserves once the extensions are executed.

With the new 4D seismic data acquired in 1Q 2025 and an Ocean Bottom Node (OBN) survey planned for 4Q 2025, Tullow expects to mature new projects and increase 2P reserves in Ghana. This is further supported by ongoing work with the Government of Ghana in relation to a Plan of Further Development for Jubilee, which covers the licence extensions and further drilling opportunities.

The report is available on the website here: https://www.tullowoil.com/investors/results-reports-and-presentations/

Notes to editors

Tullow is an independent energy company that is building a better future through responsible oil and gas development in Africa. Tullow's operations are focused on its core producing assets in Ghana. Tullow is committed to becoming Net Zero on its Scope 1 and 2 emissions by 2030, with a Shared Prosperity strategy that delivers lasting socio-economic benefits for its host nations. The Group is quoted on the London and Ghanaian stock exchanges (symbol: TLW). For further information, please refer to: www.tullowoil.com.

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This announcement contains inside information for the purposes of Article 7 of the Market Abuse Regulation (EU) No 596/2014 (as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 as amended by virtue of the Market Abuse (Amendment) (EU Exit) Regulations 2019). Upon publication of this announcement, this inside information will be considered to be in the public domain. The person responsible for arranging the release of this announcement on behalf of Tullow is Adam Holland, Company Secretary.

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