Pegasus supported the British intervention in the Russian Civil War between May and September 1919 and was based at Archangel. The ship returned to Rosyth and was briefly decommissioned. She recommissioned on 2 December 1919 and was transferred to the Mediterranean Fleet in March 1920. Pegasus ran aground on 9 March off Kerch, but was pulled off without suffering any significant damage.
Pegasus, a ship involved in British intervention during the Russian Civil War, underwent various stages of deployment and maintenance between May and September 1919, including its base at Archangel, temporary decommissioning, recommissioning, and transfer to the Mediterranean Fleet.  The ship encountered an incident where it ran aground off Kerch on March 9th but was successfully refloated without major damage.