On her return voyage the frigate searched for enemy U-boats that plagued Allied shipping at the approaches to the Straits of Gibraltar, and arrived at Boston on 20 January 1945.

During the early months of 1945, Knoxville escorted convoys across the submarine-infested Atlantic and occasionally she was dispatched for anti-submarine warfare (ASW) search operations.

Following her final escort cruise to the Azores, the patrol frigate arrived at Philadelphia on 1 June for conversion to a weather ship.

Knoxville cleared Philadelphia on 17 June and two weeks later took position on air-sea rescue and weather stations off Newfoundland.

Upon completion of her tour Knoxville returned to Charleston, South Carolina, where she was decommissioned on 13 June 1946 and was sold 22 September 1947 to the Dominican Republic.