3 November 2021

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Stanley-5 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.

Stanley-5 has been drilled to the target depth, logged and cased. Several Yegua sands from 4200-4800 feet have been identified as oil bearing from logs and sidewall cores. The well be completed for production and flow rates will be published when available.

Commenting on progress, John W Barr, Chairman, said: "This fifth successful well at Stanley is the next step to building on our delivery against the strategic objective to increase production, in addition to the recent successful wells drilled at Falcon and Winters.

"The combination of these developments, increased equity at our Stanley and Falcon projects and the much stronger oil and gas sales prices, means increased revenues and growth.  The higher prices should also increase the potential value of the Cinnabar redevelopment project, where technical work continues to identify drilling locations."

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