HMCS Loos was one of twelve Battle class naval trawlers used by the Royal Canadian Navy (RCN). Built by the Kingston Shipbuilding Company and launched in September 1917, she was commissioned in August 1918. Decommissioned in 1920, Loos was transferred to the Department of Marine and Fisheries, where she was used as a lighthouse supply ship. Sold in 1937, she was re-acquired by the RCN in December 1940 and converted to a gate vessel, spending part of the war at Shelburne, Nova Scotia. Returned to Marine Industries Limited in 1945, Loos was broken up in 1949.