Comox was ordered on 23 August 1937. She was laid down on 5 February 1938 by Burrard Dry Dock Co. Ltd. at Vancouver and launched on 9 August later that year. She was commissioned into the Royal Canadian Navy on 23 November 1938.
Comox was initially assigned to the west coast. At the onset of the Second World War, she remained at Esquimalt carrying out local patrol duties. In March 1940, she and her sister ship HMCS Nootka were reassigned to the east coast. Arriving in April 1940 she spent the rest of the war performing minesweeping duties for Halifax Harbour. Along with her sister ship, HMCS Fundy, she rescued survivors of the torpedoed Liberty ship SS Martin Van Buren on 15 January 1945.
Comox was paid off on 27 July 1945. She was sold in 1946 for commercial service and converted to the tug boatSung Ming.