[4][6][note 1] Shawmut was put into service by the Boston Steamship Company in association with the Northern Pacific and Great Northern Railways acting as booking agents with monthly passenger and freight sailings from Puget Sound ports of Tacoma and Seattle, Washington and Victoria, British Columbia to Yokohama, Kobe and Moji, Japan; Shanghai and Hong Kong, China and Manila, Philippines.

[9] She sailed on 22 August with a stop at Seattle before proceeding to sea that night and reached Yokohama 12 September unloading a small consignment.

[9] The lumber was destined for Shanghai, but the ship was too large to reach the docks on arrival 20 September and had to unload by lighter taking until 13 October before departure for Hong Kong.

[11] Shawmut had grounded off the coast of China in the fall of 1904 due to weather suffering loss of her rudder, propellers and suffering a double fracture to her stern frame and "spectacle" supports for her propellers but, after repair in an overseas dry dock, managed a return to home waters and one round trip before making permanent repairs.

[12][13] By 1907 predictions of economic trouble had become fact with Shawmut and Tremont withdrawn from Pacific service and replaced in the Philippine trade by the British firm of Andrew Weir and Company.

[16][2] Both ships played a crucial role in building the canal, bringing workers and supplies, notably massive amounts of cement, from New York to Panama for the construction project.

(Her sister ship Cristobal had made the first unofficial transit on 3 August, delivering a load of cement, while an old French crane boat Alexandre La Valley had crossed the canal from the Atlantic in stages during construction, finally reaching the Pacific on 7 January.

[19] The ship was assigned to the Atlantic Fleet's Cruiser and Transport Force making two round-trip voyages from the United States to France returning troops home.

Two years later, the Bernstein Line in Panama acquired the ship and renamed her back to Ancon before sending her to Italian shipbreakers, arriving on 26 October 1950.