Intended as a shore bombardment vessel, M25's primary armament was a single 9.2 inch Mk VI gun removed from the Edgar-class cruiser HMS Endymion.

She was equipped with a four-shaft Bolinder four-cylinder semi-diesel engine with 640 horsepower that allowed a top speed of eleven knots.

She was laid down at the Sir Raylton Dixon & Co. Ltd shipyard in March 1915, launched on 24 July 1915, and completed in September 1915.

In June 1919, M25 moved to Archangel and her shallow draught enabled her to travel up the Dvina River to cover the withdrawal of British and White Russian forces.

M25 and her sister ship M27 were unable to be recovered when the river level fell and were scuttled on 16 September 1919 after running aground.