Commissioned at Quebec City on June 20, 1942, Lachine arrived at Halifax on July 4 and, after repairs and workups, was assigned to Sydney Force in September. In October she was transferred to WLEF, and in June, 1943, became a member of EG W-6, one of the force's newly created escort groups. She served with Halifax Force from June, 1944 until VE-Day, and on July 31, 1945, was paid off at Shelburne. During the war she underwent two refits: the first, at Dalhousie, N.B., from October to November 1943; the second, at Luxemburg, from December, 1944 to March, 1945, followed by workups in Bermuda. An intended transfer to the marine section of the RCMP as Starnes did not materialize, and Lachine was sold in 1945 for conversion to a salvage tug.