From 1900 she served as troop ship during the Second Boer War, but in June 1901 she went aground while crossing the Durban Bar and had to leave for repairs in the United Kingdom. She was escorted from Las Palmas by HMS Furious and arrived at Sheerness 21 August 1901, proceeding to Chatham for repairs the following day. She was paid off at Chatham 18 September 1901.
During the First World War, Sappho and her sisters saw service off the British Isles as hastily converted minelayers. In May 1918, Sappho was ordered to be scuttled in the mouth of Ostend harbour in Belgium following the failed First Ostend Raid. The Second Ostend Raid operation (of which Sappho was a part) was intended to block the harbour mouth and prevent the transit of German U-boats and other raiding craft from Bruges to the North Sea. Whilst travelling from Dunkirk to Ostend on the day of the attack however, Sappho suffered severe engine damage in a minor boiler explosion and was forced to retire, taking no part in the partial success of the raid. She was not used again during the war, and was scrapped in 1921.