Peoria's shakedown voyage (or sea trial) commenced on 12 January 1945, bound for the North Atlantic Ocean around Bermuda, and returned successfully to Norfolk, Virginia.
Peoria's first mission, begun on 4 March, was to sail with a convoy for the British Crown colony of Gibraltar. Peoria then continued on to Mers El Kébir, Algeria, concluding her journey on 19 March. She joined a returning convoy from Oran on 27 March, assigned with escorting it to the United States. Peoria then spent a brief amount of time at New York City, until she was called out for use in anti-submarine training at Casco Bay, Maine. On 7 May, she departed Casco Bay bound for New London, Connecticut. Peoria arrived at New London in time for VE day, as World War II concluded. Peoria spent two weeks training submarine crews at New London.
On 21 May, Peoria left New London, assigned to Charleston, South Carolina, where she was to be fitted out for patrol duty in the Atlantic. Peoria was used for weather station work from 21 June, visiting stations in North Atlantic ports from Bermuda to Iceland for a further year.