Appointment of CFO.

3 June 2025

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Appointment of CFO

Mosman Oil and Gas Limited (AIM: MSMN) the helium, hydrogen and hydrocarbon exploration, development and production company, announces that it has appointed Tina Loh CA, a partner of CDTL Accountants and Advisors ("CDTL"), as Chief Financial Officer (non-board), with immediate effect. Ms Loh is also the Company Secretary.

Pursuant to an agreement with CDTL, aggregate annual fees payable by the Company to CDTL for financial and company secretarial services, including the provision of Ms Loh's services are AU$180,000. Any additional fees payable for ad hoc work will be subject to independent board approval.

Related Party Transaction

CDTL is a related party of the Company as defined under the AIM Rules for Companies (the "AIM Rules"), due to the interest of Carl Dumbrell, Chairman of Mosman, in CDTL, and the agreement with CDTL to appoint Ms Loh as CFO is therefore considered a Related Party Transaction pursuant to Rule 13 of the AIM Rules.

Andy Carroll, Nigel Harvey and Graham Duncan, being the directors independent of CDTL, consider, having consulted with the Company's Nominated Adviser, SP Angel Corporate Finance LLP, that the terms of the agreement with CDTL are fair and reasonable insofar as the Company's shareholders are concerned.

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.