"Galatea" joined the Mediterranean Fleet on commissioning and except the period from March till September 1938 acted as flagship, Rear Admiral (Destroyers). Based in Malta, upon the outbreak of the Spanish Civil War she was active in joint patrols enforcing the non-intervention policy, periodically in co-operation with "Deutschland" and Italian destroyers. Later deployed in Alexandria, she remained on alert in course of the Italian invasion of Abissynia. In the spring and summer of 1938 on refit in Devonport, she was recommissioned for the Mediterranean, deployed at Malta and Alexandria. On 29 March 1939 in Gandia "Galatea" took on board the leader of the National Defence Council colonel Segismundo Casado and his entourage; the following day she sailed off and on 31 March Casado was transferred to the hospital ship "Maine".