Rockhopper Regulatory News (RKH)

20 May 2026

Rockhopper Exploration plc

("Rockhopper" or the "Company")

Sea Lion Operator's Update

Rockhopper Exploration plc (AIM: RKH), the oil and gas company with key interests in the North Falkland Basin ("NFB"), notes the recent update published by Navitas Petroleum LP ("Navitas" or the "Operator") on Sea Lion development progress.

As previously disclosed the first two phases of the Sea Lion development is set to use an FPSO, being the Aoka Mizu, which shall have production capacity of 55k bopd (19.25k bopd net to Rockhopper). Navitas has today provided an update that it is investigating accelerating the development of subsequent phases of the Sea Lion development and has accordingly signed a Memorandum of Understanding ("MOU") for an additional FPSO which could increase the Sea Lion production capacity by a further 125,000 bopd (43.75k bopd net to Rockhopper). There is no guarantee that this MOU will convert to legally binding agreements.

Navitas has also updated that due to the conflict in Iran, it has decided to change the location for the upgrades of the Aoka Mizu FPSO from the Middle East to Asia. This change will add an approximate US$45 million to the current development budget. Rockhopper benefits from a loan from Navitas covering 2/3 of its 35% equity requirement for Phase 1 of the Sea Lion development. Accordingly, the net increase in Rockhopper's equity costs is US$5.25 million and Rockhopper remains funded for Phase 1 of the project.

Navitas reports other progress on the Sea Lion development as follows:

· The development works on the Falkland Islands have commenced and at this stage are focused on preparing the dock and shore base. Later this year, works will also commence for the construction of worker accommodation as well as additional infrastructure works in preparation for the commencement of drilling activity.

· The manufacturing of long lead items for the Phase 1 is ongoing.

· In early May 2026, the owner of the Aoka Mizu FPSO provided an update that production by the current operator had concluded and, by the end of May, disconnection works will be completed and the Aoka Mizu FPSO will sail to the shipyard for upgrade work to adapt it to Sea Lion's requirements.

· Drilling and completion works are scheduled to commence at the beginning of 2027. First oil from the Phase 1 is still currently expected in H1 2028.

Samuel Moody, Chief Executive Officer of Rockhopper, commented:

"We are delighted that the project is on track having taken the prudent decision in the light of the security situation arising from the Iran conflict to move the FPSO work from the Middle East to Asia. We are equally excited at the prospect that the development of additional barrels might be accelerated with the signing of the MOU for a second FPSO giving the opportunity to add a further 125,000 barrels per day of production to the 55,000 barrels per day from the first two phases."

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 / James Asensio / 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.