30 August 2019

Mosman Oil and Gas Limited

                                            ("Mosman" or the "Company")

Stanley-3 Update

Mosman Oil and Gas Limited (AIM: MSMN) the oil exploration, development and production company, advises an update in respect to the Stanley-3 well in Texas.

The Stanley-3 well was drilled to the planned total depth of 5144 feet. After evaluation of drilling data, wire-line logs, and sidewall cores, production casing was run to the total depth of the well. Several potential pay zones have been identified.

The rig is now on-site and preparing to complete the well. The initial completion will consist of a perforation interval of four feet located near the top of the Yegua 4800 foot Sand.

Flow rates and further details in respect of the potential pay zones will be provided when data is available.

John W Barr, Chairman, said: "We have a 100% success rate at Stanley with three successful wells.

"Given the success of this well, Mosman looks forward to getting flow rates soon and near-term consideration of Stanley-4. Mosman executives will meet various parties in Houston and on site to consider this and other matters."

"The Company continues to meet its stated objectives of building production"

Competent 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

Certain information contained in this announcement would have been deemed inside

information for the purposes of Article 7 of Regulation (EU) No 596/2014 until the release of this announcement.

 Enquiries:

Updates on the Company's activities are regularly posted on its website www.mosmanoilandgas.com