Jamaica Update: Commencement of Piston Coring

United Oil & Gas PLC / Index: AIM / Epic: UOG / Sector: Oil & Gas

23 February 2026

United Oil & Gas plc

("United" or "the Company")

Completion of Stage 2 and Commencement of Stage 3 Piston Coring - Walton Morant Licence, Jamaica

United Oil & Gas Plc (AIM: UOG), the oil and gas company with a high-impact exploration asset in Jamaica and a development asset in the UK, is pleased to announce the completion of Stage 2 of its Surface Geochemical Exploration ("SGE") programme and the commencement of Stage 3 piston coring operations on the Walton-Morant Licence offshore Jamaica.

Highlights

· Stage 2 seabed heat-flow measurements successfully completed

· Stage 3 piston coring now underway - the critical phase of the programme

· Up to 42 cores planned, primarily within the Walton Basin near the key Colibri, Streamertail and Oriole prospects, with select key locations in the Morant basin also identified

· Programme designed to physically confirm an active petroleum system and further de-risk the licence

Operational Update

Stage 2 heat-flow measurements have now been completed and will provide valuable technical information for future geological modelling. Data from the previously completed Stage 1 high-resolution multibeam echosounder ("MBES") acquisition have also been integrated with the existing seismic dataset. This has resulted in the identification of numerous seabed features of interest and the selection of 42 optimal piston core locations for Stage 3 of the survey.

Figure 1 (above): Conceptual illustration of MBES seabed mapping integrated with seismic interpretation to identify seabed features of interest and optimise piston core locations (not to scale).*

Stage 3 piston coring is now underway, with up to 42 cores planned across priority areas, predominantly within the Walton Basin and in proximity to the Company's Colibri, Streamertail and Oriole prospects, where existing 3D seismic and supporting datasets indicate potential hydrocarbon migration. Additionally, key locations in the Morant basin will also be cored.

This stage of the survey will recover seabed sediment samples for geochemical analysis to test for thermogenic hydrocarbons, which if present, will provide direct physical evidence of an active petroleum system offshore Jamaica.

The piston coring operations are expected to take approximately one week, subject to weather conditions, with samples then shipped to Houston, Texas for laboratory analysis.

The SGE programme represents a key operational step toward further de-risking the Walton-Morant Licence and advancing the project's technical evaluation and commercial discussions.

Brian Larkin, CEO of United Oil & Gas, commented:

"The completion of heat-flow measurements and commencement of piston coring marks a major step forward in our Jamaica exploration programme. The integration of the acquired data has allowed us to optimise coring locations in the Walton Basin, including near our key Colibri, Streamertail and Oriole prospects, as well as at key locations in the Morant Basin.

Piston coring is the defining phase of this programme, providing the opportunity to physically confirm the presence of thermogenic hydrocarbons offshore Jamaica. We look forward to completing operations and updating the market in due course."

Additional Information

A recent discussion with CEO Brian Larkin outlining progress of the SGE programme and next steps is available to view here:

https://www.youtube.com/watch?v=PDHGGdWz9pY

"On the Rocks" podcast episode 2, where United discuss the completed Stage 1 MBES and next steps of the SGE Jamaica survey 2026 is available to view here:

https://youtu.be/dMAtCalsI-o

"On the Rocks" podcast episode 1, where United discuss the Evidence for an active Petroleum System offshore Jamaica, is available to view here:

https://youtu.be/Ui9krmLFXp4

*Image credit: NOAA Photo Library (via Flickr) - "Artist's conception of multibeam sonar on NOAA Ship NANCY FOSTER" (Image ID: fis01334; Credit: NOS/NCCOS/CCMA), licensed CC BY 2.0. Image cropped/adapted.

**ENDS**

Beaumont Cornish Limited ("Beaumont Cornish") is the Company's Nominated Adviser and is authorised and regulated by the FCA. Beaumont Cornish's responsibilities as the Company's Nominated Adviser, including a responsibility to advise and guide the Company on its responsibilities under the AIM Rules for Companies and AIM Rules for Nominated Advisers, are owed solely to the London Stock Exchange. Beaumont Cornish is not acting for and will not be responsible to any other persons for providing protections afforded to customers of Beaumont Cornish nor for advising them in relation to the proposed arrangements described in this announcement or any matter referred to in it.

Notes to Editors

United Oil & Gas is an oil and gas company with a development asset in the UK and a high impact exploration licence in Jamaica.

The business is led by an experienced management team with a strong track record of growing full cycle businesses, partnered with established industry players and is well positioned to deliver future growth through portfolio optimisation and targeted acquisitions.

United Oil & Gas is listed on the AIM market of the London Stock Exchange. For further information on United Oil and Gas please visit www.uogplc.com