Assigned to the Naval Overseas Transportation Service to operate on a United States Army account, Berwyn moved from Sparrows Point to Baltimore, Maryland, and loaded a cargo of ordnance bound for France.

The blaze stubbornly resisted efforts to put it out, but the firefighters contained it and finally extinguished it early on 21 October 1918.

Making landfall at the Île d'Yeu in France on 16 November 1918—five days after Armistice with Germany had ended World War I—Berwyn proceeded to Quiberon Bay, where she anchored that afternoon.

Shortly after loading a cargo of hay, food, and gasoline, Berwyn left Baltimore for Hampton Roads, Virginia.

On 27 January 1919, she received orders to proceed to Nantes because unloading facilities at St. Nazaire were filled to capacity.

Shortly before making landfall on the United States East Coast, she received orders to put into New York City, and reached Pier 94, North River, dropping anchor at the foot of 57th Street in Manhattan at 11:30 hours on 2 May 1919.

During the summer of 1919, SS Berwyn carried general cargo to Liverpool, arriving there on 16 June 1919, before returning to Hampton Roads on 19 August 1919.

She was wrecked on 6 September 1920 on the Khuriya Muriya Islands in the Arabian Sea at approximately 17°44′N 056°38′E / 17.733°N 56.633°E / 17.733; 56.633 (SS Berwyn).