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 the German cruiser Deutschland and Italian destroyers.

[1] After the outbreak of Second World War she was ordered home, and between February and March 1940 she took part in the operations to intercept Axis merchantmen attempting to break out of Vigo.

In July 1941 she joined the Mediterranean Fleet via the Red Sea, and by November was based at Malta with Force "K", operating against the Axis supply convoys to North Africa.

On 15 December 1941 before midnight Galatea was torpedoed and sunk by the German submarine U-557 off Alexandria, Egypt with the loss of 470 crew.