Decatur was designated lead vessel of the 1st Torpedo Flotilla, with which she conducted drills and maneuvers along the eastern seaboard and in the Caribbean. In December 1903, the flotilla departed Norfolk for the Asiatic Station. Sailing by way of the Suez Canal, it arrived at Cavite, Philippine Islands on 14 April 1904.
Decatur exercised along the China coast and cruised in Philippine waters until placed in reserve at Cavite on 5 December 1905. For the next three years, she made infrequent cruises, including one to the southern Philippines in January and February 1908 and Saigon in May 1908.
Placed out of commission 18 February 1909, Decatur was placed in commission in reserve on 22 April 1910 and in full commission on 22 December. She resumed operations with the Torpedo Flotilla, cruising in the southern Philippines and between ports of China and Japan until 1 August 1917, when she departed for the Mediterranean.
Assigned to US Patrol Squadrons, she arrived at Gibraltar on 20 October 1917 for patrol and convoy duty in both the Atlantic and Mediterranean until 8 December 1918. Decatur arrived at Philadelphia on 6 February 1919 and was decommissioned there 20 June 1919. She was sold 3 January 1920.