First Well in Malaysia Campaign Flows at 3000 bopd

24 June 2026 - Singapore: Jadestone Energy plc (AIM:JSE) (the "Company" and together with its subsidiaries, "Jadestone" or the "Group"), an independent upstream production and development company focused on the Asia-Pacific region, is pleased to announce that the first well in the 2026 Malaysia infill drilling campaign on the PM323 PSC has been successfully drilled and brought online at ~3,000 bopd.

The 2026 Malaysia drilling campaign originally included two firm wells and a third contingent well targeting the southwest extension of the East Belumut field, which was identified in the 2023 infill programme. Based on the strong performance of the first well and the subsurface data gathered during drilling of the second well, the third well has now been confirmed and drilling has commenced. The Group's 2026 capital expenditure guidance[1] of US$50-80 million remains unchanged.

The first well in the 2026 campaign, EBA-18ST3, was drilled ~20% below budget. This is an excellent result considering the 1,200 metre horizontal reservoir section in the well at a total measured depth of 4,866 metres, the longest of any well drilled to date on the East Belumut field.

"Our established operating capabilities in Malaysia, combined with our refreshed focus on operational excellence, have been further validated by the outcome of the EBA-18ST3 well. The result is an excellent start to this year's drilling campaign and will significantly increase our Malaysia production in the near-term against the backdrop of strengthened Brent oil prices, with our most recent Malaysia oil sales attracting a US$14/bbl premium to Brent.

Following on from the significant progress on our Vietnam project earlier this year and the successful debt refinancing, this is further evidence of a business that is executing on its plan and strategy. We look forward to updating the market further on the second well in the campaign in the near-future."