28 October 2021

Mosman Oil and Gas Limited

("Mosman" or the "Company")

EP 145 Update

Mosman Oil and Gas Limited (AIM: MSMN) the oil exploration, development, and production company, announces an update on EP 145 situated in the Amadeus Basin in central Australia.

Exploration activities have been ongoing throughout the current calendar year including the airborne gradiometry acquisition and related geological interpretation work previously referred to. The Covid19 pandemic has disrupted and delayed activities and continues to be an issue that must be dealt with.

The technical work analysed the recently acquired gravity data and integrated it with regional gravity, magnetic and seismic data. This is the first permit wide data acquisition and evaluation and has provided positive clarification of the basement structure and composition. Given the results and the excellent work by Geognostics, Mosman wish to undertake a follow up study and are in discussion with Geognostics regarding this work. The project will aim to further update the geological model and petroleum/helium play.

Some of the results were included in Mosman's presentation at the NT Resources Seaaoc Conference in Darwin, and this presentation will be shortly made available on Mosman website. In addition, the Central Land Council (CLC) has rescheduled the proposed Sacred Site Clearance visit to the permit. The visit by representatives of the local communities and staff of the CLC will now occur in November and is budgeted to cost C$46,000. This is a statutory requirement and should provide approval for seismic lines in due course.

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.

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www.mosmanoilandgas.com