3 June 2025

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Appointment of Non-Executive Director

Mosman Oil and Gas Limited (AIM: MSMN) the helium, hydrogen and hydrocarbon exploration, development

and production company, is pleased to announce that it has appointed Andrew Scott as Independent Non-

Executive Director.

Mr. Andrew Scott brings extensive strategic advisory experience to resources companies listed on the LSE

and ASX.

He has a proven track record of steering small and mid-cap firms through intricate transactions and strategic growth initiatives, working closely with corporate financiers.

His expertise spans market dynamics and stakeholder engagement, developed through roles at leading advisory firms in Australia and the UK. Andrew holds a Bachelor of Science (BSc) in Mathematics and Statistics and currently serves as a Non-Executive Director of AIM-listed ECR Minerals.

Mosman Chairman, Carl Dumbrell, commented: "Andrew's deep industry expertise in the resources sector will bring significant value to Mosman as we continue to drive growth and deliver value for our shareholders. We warmly welcome Andrew to the Mosman Board and look forward to his contributions to our strategic vision."

AIM Rules disclosures

Andrew Maccrae Scott, aged 39, currently holds or has held the following directorships in the last five years:

Mr Scott currently holds no ordinary shares or options in the Company.

Enquiries:

Updates on the Company's activities are regularly posted on its website: www.mosmanoilandgas.com

Notes to editors

Mosman (AIM: MSMN) is a helium, hydrogen and hydrocarbon exploration, development, and production company with projects in the US and Australia. Mosman's strategic objectives remain consistent: to identify opportunities which will provide operating cash flow and have development upside, in conjunction with progressing exploration. The Company has several projects in the US, in addition to exploration projects in the Amadeus Basin in Central Australia.