FS-395—an inter-island freighter and cargo vessel completed for the United States Army on 2 January 1945 at Decatur, Alabama, by the Ingalls Shipbuilding Corp.—was subsequently inspected by the Navy and accepted for service at the Naval Operating Base (NOB), Subic Bay, Philippine Islands, on 22 February 1947.

FS-395 was later given the name Whidbey and classified a miscellaneous auxiliary, AG-141; she was commissioned at Naval Operating Base (NOB), Guam, while moored alongside SS Hamilton Victory on 8 August 1947.

Shutting down the port main engine, the auxiliary's crew battled the small fire for only a short time before they succeeded in putting it out, while, topside, heavy seas carried away one of the snip's lifeboats.

By 0413, heavy waves were breaking over the port and starboard sides of the ship; changing course at that instant, Whidbey suddenly ground onto a reef at 0418.

In an effort to look into the health and welfare of the inhabitants of all of the populated islands within the two and one-half million square miles of the Trust Territory, the Navy began a medical survey of those isles in 1948.

Whidbey's performance of duty enabled the Navy to ascertain a complete picture of both the common and the rare diseases that occurred in the territories.

When the Navy relinquished its administrative duties to the U.S. Department of the Interior, Whidbey's role changed; her operations took on a different complexion in light of the Korean War that had broken out in the summer of 1950.

After touching at the Chinese naval base in the Pescadores, at Makung, until 15 May, Whidbey stopped briefly at Kaohsiung before she visited Hong Kong, en route to Sasebo.