The ship, originally designated a "patrol gunboat," PG-191, was ordered by the United States Maritime Commission under a United States Navy contract as the first USS Hoste. She was reclassified as a "patrol frigate," PF-83, on 15 April 1943 and laid down by the Walsh-Kaiser Company at Providence, Rhode Island, on 7 September 1943. Intended for transfer to the United Kingdom, the ship was renamed Nyasaland by the British prior to launching and was launched on 6 October 1943, sponsored by Mrs. William A. Cahir.
Transferred to the United Kingdom under Lend-Lease on 31 July 1944, the ship served in the Royal Navy as HMS Nyasaland (K587) on patrol and escort duty. On 17 December 1944, she sank the German submarine with depth charges in the North Atlantic Ocean south of Cork, Ireland, at 51.2667°N -13°W. On 4 February 1945, she shared credit with the British frigates,, and for sinking the German submarine in a depth-charge attack in the North Channel off Malin Head, Ireland, at 55.2833°N -51°W. On 2 March 1945, she rescued 42 survivors of the British merchant ship SS King Edgar, which the German submarine had sunk in St. George's Channel at 52.0833°N -47°W.
The United Kingdom returned Nyasaland to the U.S. Navy on 15 April 1946. She was sold to the Sun Shipbuilding & Dry Dock Company of Chester, Pennsylvania, on 10 November 1947 for scrapping.