"London" arrived at Lemnos on 23 March 1915, and over the next month, she took part in preparations of the British and French fleet for the landings at Cape Helles and at Anzac Cove, the beginning of the land portion of the Gallipoli Campaign. On her arrival in the eastern Mediterranean, "London" joined the 2nd Squadron, commanded by Rear Admiral Cecil Thursby. She supported the main landings at Gaba Tepe and Anzac Cove on 25 April 1915. "London" arrived off the landing beach at about midnight, along with "Queen" and "Prince of Wales"; they were tasked with supporting the landing of the 3rd Australian Brigade. "London" covered the left side of the beach. Over the course of the landing, "London" and the other covering ships provided covering fire as the ANZAC troops advanced inland and helped to suppress Ottoman artillery.