4 September 2023

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Board Changes

Mosman Oil and Gas Limited (AIM: MSMN) the oil and gas exploration, development, and production company, announces that John W Barr, Chairman and John Young, Non Executive Director have informed the Board of their decision to step down from the Board.

John W Barr has given notice of his resignation as a Director, effective 30 September 2023. John has also given termination notice under his executive services contract as a Director of Kensington Advisory Services Pty Ltd contract which has a six month termination period.

John Young, Non Executive Director, has also resigned from the Board leaving the Company with immediate effect.

Andy Carroll, Technical Director and Executive Director and Nigel Harvey, Non Executive have commenced a process to review and appoint new Directors and further updates will be provided in due course as appropriate.

Business Plan

The strategy remains to build USA production and keep high potential upside helium, hydrogen and hydrocarbon exploration in Australia. The Company's wider corporate review continues and costs will be optimized to ensure ongoing financial stability.

On behalf of the Board, Andy Carroll, Technical Director commented: "We thank John W Barr for leading the Company from inception, through IPO and the ups and downs of exploration, development and production. We also thank John Young for his contribution since the formation of the Company and wish him well in his future endeavours.

"The immediate focus is the appointment of a Non Executive Director and the operations are continuing to progress.  We will provide an update in due course."

Market Abuse Regulation (MAR) Disclosure

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014 ('MAR') which has been incorporated into UK law by the European Union (Withdrawal) Act 2018. Upon the publication of this announcement via Regulatory Information Service ('RIS'), this information is now considered to be in the public domain.

Enquiries:

Updates on the Company's activities are regularly posted on its website:

www.mosmanoilandgas.com

Notes to editors

Mosman (AIM: MSMN) is an oil 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 of its existing exploration permit and permit application. The Company has several projects in the US. In addition to exploration projects in the Amadeus Basin in Central Australia.