 On commissioning, "Dartmouth" joined the Atlantic Fleet, being attached to the Third Battle Squadron from 1912 to 1913.After a 1913 cruise to the Mediterranean Sea, she was briefly attached to the Second Light Cruiser Squadron at Devonport to participate in the 1913 Naval Manoeuvres before leaving to join the East Indies Squadron of the Eastern Fleet.On the outbreak of the First World War, "Dartmouth" was docked at Bombay, but was soon returned to sea, escorting a troop convoy from Karachi to Mombasa in Kenya and then taking part in the search for the German cruiser .