Stanley-5 well update

18 October 2021

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Stanley-5 well update

Mosman Oil and Gas Limited (AIM: MSMN) the oil exploration, development, and production company, announces an update on the Stanley-5 well in Polk County, East Texas.

The well is now scheduled to be drilled after the current well at Winters is completed and the rig is relocated the short distance to Stanley-5.

Stanley-5 is a development well targeting the Yegua formation, at approximately 5,000 feet.

Following the acquisition of Nadsoilco LLC in July this year, Mosman's interest in this well will be c36.5%. Mosman will fund its share of the USD 350,000 drilling costs from existing cash resources.

John W Barr, Chairman, said: "Mosman is pleased with the current drilling activity that we had planned for this year to achieve the strategic objective of increasing production."

Qualified Person's Statement

The information contained in this announcement has been reviewed and approved by Andy Carroll, Technical Director for Mosman, who has over 35 years of relevant experience in the oil industry. Mr. Carroll is a member of the Society of Petroleum Engineers.

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 inside 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