Harbour Energy plc

("Harbour")

8 December 2025

Sale of Natuna Sea Block A and Tuna in Indonesia

Harbour Energy plc announces that it has entered into a Sale and Purchase Agreement to sell its operated interests in the producing Natuna Sea Block A field and the Tuna development project in Indonesia to Prime Group for a cash consideration of $215 million.  

The sale is subject to customary regulatory approvals and completion is targeted for Q2 2026. 

Steve Cox, Managing Director of Harbour's Indonesia Business Unit, commented:

"This transaction marks a key milestone for Harbour in Indonesia and supports our strategy to focus capital and resources on our most competitive and material opportunities.

"It is also a significant moment for our colleagues in the country, whose hard work and commitment have built Natuna Block A and Tuna into high quality assets over many years. I wish them well as they enter a new chapter under the experienced ownership of Prime Group."

Notes to editors:

Prime Group has upstream and downstream oil and gas businesses in Indonesia, including a 25% interest in the producing Natuna Sea Block B field.

The Natuna Sea Block A sale has an effective date of 1.1.2025 and the Tuna sale will be effective on completion. The consideration is subject to customary completion adjustments.

Harbour has a 28.67% operated interest in Natuna Sea Block A which produced c.4 kboepd (net) in the nine-month period to 30 September 2025. As at year end 2024, Harbour had booked 2P reserves of 7.4 mmboe in relation to Natuna Sea Block A.

Harbour has a 50% operated interest in the Tuna project. As at year end 2024, Harbour had booked 2C resources of 54 mmboe in relation to the Tuna project.

Following completion of the transaction, Harbour will maintain a presence in Indonesia through its interests in the Andaman Sea discoveries.

Houlihan Lokey is acting as sole financial advisor to Harbour on the transaction.