Commissioned at Montreal on May 12, 1941, Napanee arrived at Halifax on May 17. She was assigned initially to Sydney Force but transferred in September to Newfoundland Command, leaving Sydney for Iceland with convoy SC.47 on September 29. She served on that route until January, 1942, when she sailed with SC.65, the first of many "Newfie-Derry" convoys she would escort until August, 1944. The worst of them was ONS.154, which lost 14 ships in December, 1942, but Napanee assisted in sinking one of its attackers, U 356, on December 27. In March, 1943, she made a side trip to Gibraltar with EG C-1, which she had joined in September, 1942. She arrived at Montreal May 22, 1943, for a five-month refit, including fo'c's'le extension, afterward working up at Pictou and joining EG C-3. She left 'Derry for the last time on August 3, 1944, refitted again at Pictou, then carried out three weeks' workup in Bermuda. On her return she joined EG W-2, on the "triangle run" until the end of the war. Paid off July 12, 1945, at Sorell, she was broken up at Hamilton in 1946.
Focsle Extended, Montreal, PQ, 19 Oct 43