USS Aztec, a 848 gross ton patrol vessel, was built in 1902 at Elizabethport, New Jersey, as the steam yacht of the same name. She was leased by the Navy in June 1917 and placed in commission late in that month. Following post-commissioning overhaul, Aztec spent the rest of World War I, and the first months following the 11 November 1918 Armistice, as flagship of the First Naval District, headquartered at Boston, Massachusetts. In addition to making inspection cruises around northern New England, she also was employed for escort and patrol duties. In late December 1918 Aztec carried Assistant Secretary of the Navy Franklin D. Roosevelt during the Victory Fleet Review in New York Harbor. She was decommissioned in mid-March 1919 and returned to her owner in August 1919.

In the early 1930s, after more than a decade of further yachting, Aztec was laid up at Boston. She was sold to a Canadian owner in 1940 and, in May of that year, taken over by the Royal Canadian Navy. Commissioned as HMCS Beaver in March 1941, the ship performed escort, patrol, tender and transportation missions in the Canadian Atlantic provinces until September 1944, when she was drydocked for repair of serious defects and, shortly afterwards, decommissioned. Beaver had no further active service and was sold in January 1946.