Result of Audit Tender

Harbour Energy plc

("Harbour" or the "Company")

Outcome of audit tender process

17 October 2025

Harbour announces that, following the conclusion of a competitive audit tender process led by the Audit and Risk Committee, the Board has approved the proposed re-appointment of Ernst & Young LLP (EY) as its external auditor to take effect from, and including, the financial year ending 31 December 2026. The re-appointment is subject to shareholder approval at the Company's 2026 Annual General Meeting.

On 31 March 2021, Harbour Energy plc (formerly known as Premier Oil plc) acquired Chrysaor Holdings Limited as part of a reverse takeover and undertook a limited audit tender, whilst stating that it would undertake a full tender in 2025 for the 2026 year end. EY was the auditor of Premier Oil plc from the period ended 31 December 2017 up to and including the period ended 31 December 2020. As a result, EY have been the Company's auditors for eight years and so another audit tender will take place no later than for the audit of the 2037 year end, to meet the requirements of a public interest entity.

Harbour Energy plc LEI: 213800YPC42DYBKVPF97