Commissioned at Quebec City on October 25, 1943, Cape Breton arrived at Halifax on November 28 and worked up in St. Margaret's Bay in January, 1944. Assigned to EG 6, a support group based at Londonderry, she left Halifax for the U.K. on February 24. She operated at various times from Londonderry, Portsmouth and Plymouth, and in April, 1944, sailed to North Russia, returning with convoy RA.S9. She was also on hand on D-Day. She returned to Canada late in 1944, arriving on November 6 at Shelburne for a major refit. This was completed in April and she was then sent to Bermuda to work up. Assigned to EG 9, she left St. John's on May 9 with convoy 1-1X.354, and later that month sailed from Londonderry direct to Vancouver. A tropicalization refit begun on June 26 was cancelled before completion and the ship was paid off January 26, 1946, after several months in reserve at Esquimalt. She was sold in 1947 and expended as a breakwater in 1948, reportedly at Kelsey Bay, B.C.