5 October 2026

Rockhopper Exploration plc

("Rockhopper")

Sea Lion Operator Update

Rockhopper (AIM: RKH), the oil and gas company with key interests in the North Falkland Basin, notes media reporting regarding the Falkland Islands and also notes the announcement made today by its partner and Sea Lion project operator Navitas Petroleum ("Navitas") which is extracted below:

'Further to investors' inquiries and the Partnership's report dated September 4, 2026 (Reference No. 2026-01-083584) regarding the speech of the Honourable President of Argentina, Javier Milei, the Partnership updates that the Government of Argentina continues its activity to impose sanctions on those involved in the Sea Lion Project, as well as on other activities in the Falkland Islands.

In this regard, and further to a report published in the media on behalf of a contractor related to the Project, according to which it will not perform work on the Sea Lion Project and will not participate in the exploration and production of oil in the Falkland Islands area, the Partnership updates that it is taking action to replace two breaching contractors and will continue to act to make adjustments to the Project, as may be required.

The Partnership clarifies that it continues the development of the Project with the full support of the Falkland Islands Government and the Government of the United Kingdom, and at this stage it estimates that no material adverse effect on the Project is expected.

The above assessments regarding the absence of a material adverse effect on the Project constitute forward-looking information as defined in the Israeli Securities Law, 5728-1968, based on the Partnership's assessments, which are based, among other things, on the information currently available to the Partnership.

Such assessments may not materialize, or may materialize in a manner materially different from that anticipated, if the replacement of the two breaching contractors is delayed or unsuccessful, or if the making of adjustments to the Project, as may be required, is delayed or unknot successful, as well as if additional contractors involved in the Project notify of refraining from activities in the Falkland Islands area and no satisfactory alternatives are not found for them, and also if there is further escalation in the activity of the Government of Argentina on this matter and additional regulatory and/or geopolitical changes occur which affect the legal and commercial assessments of the Partnership and its advisers.

For further details regarding the risks in activity in the Falkland Islands territory, see Section 8.15 of the Partnership's Annual Report for 2025 (Reference No. 2026-01-023779).'

The full announcement by Navitas can be found here: https://maya.tase.co.il/he/reports/1773776

Enquiries:

Rockhopper Exploration plc

Sam Moody - Chief Executive Officer

Tel. +44 (0)20 7390 0230 (via Vigo Consulting)

Canaccord Genuity Limited (NOMAD and Joint Broker)

Henry Fitzgerald-O'Connor / Charlie Hammond

Tel. +44 (0)20 7523 8000

Peel Hunt LLP (Joint Broker)

Richard Crichton / Georgia Langoulant

Tel. +44 (0)20 7418 8900

Vigo Consulting

Patrick d'Ancona / Ben Simons / Fiona Hetherington

Tel. +44 (0)20 7390 0234

Notes to Editors

Rockhopper Exploration plc is a UK-based oil and gas exploration and production company with key interests in the Falkland Islands. The Company holds a 35 per cent interest in licences in the North Falkland Basin, where it has sanctioned the development of the significant Sea Lion field, originally discovered by the Company in 2010.

Rockhopper's shares are quoted on the AIM market of the London Stock Exchange under the ticker RKH.

For more information, visit the Company's website at www.rockhopperexploration.co.uk.