Vecta Project Billy Goat Update.

20 May 2025

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Vecta Project Billy Goat Update

Mosman Oil and Gas Limited (AIM:MSMN) the helium, hydrogen and hydrocarbon exploration, development and production company, announces an update on the Vecta Project in Colorado, US.

Mosman has been in discussions with a local helium business that has expressed interest in acquiring the first well and associated contractual rights of the Billy Goat lease AMI area lease.

The Board is seriously considering this offer as co-operation with this party could be the fastest path to production and commercialisation for any helium discovered in the Billy Goat Area.

The Billy Goat AMI lease area first well was drilled to circa 720 feet TD and casing set on 16 May 2025. Further well information will not be released until after these discussions have been finalised.

Andy Carroll, Chief Executive Officer of Mosman, said: "We are pleased that this potential opportunity has arisen. Mosman will only agree to a change that it considers more favourable to the Company and shareholders. We look forward to providing further updates 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 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.