Name ship of her trend-setting class of "Cadillacs," St. Laurent was built by Canadian Vickers Ltd., Montreal, and commissioned on 29 October 1955. In February 1956 she proceeded to the U.S. Trials Centre at Key West, Florida, for three months' evaluation, after which she visited Washington and then the U.K., in the course of the latter excursion escorting HMY Britannia on a state visit to Sweden. On 2 February 1960, St. Laurent, by then stationed on the west coast, departed Esquimalt with two of her sisters on a 2 1/2-month Pacific cruise, visiting Long Beach, Pearl Harbour, Yokosuka, Okinawa and Hong Kong. She was test-fitted with VDS prior to being converted to a DDH at Burrard Dry Dock, Vancouver. Re-commissioned on 4 October 1963, she returned to the east coast. Paid off on 14 June 1974, the now aging ship remained in Halifax as a source of spare parts for her sisters. On 1 January 1980, she left under tow for Brownsville, Texas, to be broken up, but on the 12th foundered in a gale off Cape Hatteras.
Re-commissioned as DDH 4 Oct 63. Paid off early, after keel damage. Sank off Cape Hatteras 12 Jan 80 while being towed to Brownsville TX for scrap.