Despite orders to the contrary, Dewey did not commission Nanshan into the U.S. Navy so she would technically be a merchant ship and, thus, would be able to access neutral ports which greatly simplified the squadron's logistics.

She coaled Dewey's victorious ships until Manila was occupied on 13 August, and continued to serve in the Philippines and on the China Station.

Aside from a brief period out of service at Cavite Navy Yard for upkeep from 29 March 1906 – 1 February 1907, Nanshan served in the Far East until 10 May 1913, when she returned to San Francisco to coal ships along the coasts of California, Mexico, and South America.

Placed out of service at Mare Island Naval Shipyard on 31 March 1914 for repairs, Nanshan was placed in full commission on 1 August with her first Navy crew.

Supply missions ranging from Alaska to Hawaii continued until 1 February 1918, when she sailed for Hampton Roads, Virginia, via the Panama Canal.