The third of the C.N. sisters, Prince Robert was purchased in December, 1939, and fitted out as an AMC, commissioning at Vancouver July 31, 1940. She left in mid-September for patrol off Mexico and Peru, and on September 25 intercepted and captured the German freighter Weser. On December 15 she left Callao, Peru for Australia to act as escort to a Canada-bound troop convoy, and in May, 1942 returned to the South Pacific for three months' escort and patrol duties under RN control on the New Zealand Station. She left Auckland on July 28, 1941 for Easter Island to investigate reports of a Japanese supply ship in the area, and arrived at Esquimalt on August 24 for a short refit. In November she escorted a shipload of ill-fated Canadian troops to Hong Kong and on her return rejoined Esquimalt Force. In August, 1942, Prince Robert was placed under USN control for duty in the Aleutians, arriving back at Esquimalt on November 4. She was paid off on January 2, 1943, for conversion to an auxiliary A/A ship, and was re-commissioned on June 7 at Vancouver, leaving Esquimalt 12 days later for the Clyde via Bermuda. In November, she was assigned to Gibraltar Command, Mediterranean Fleet, and employed as A/A escort to U.K.-Sierra Leone and U.K.-Mediterranean convoys. Though reassigned to Plymouth Command in January, 1944, she remained at the same duties, and from June to August escorted Mediterranean convoys. In September Prince Robert left Plymouth for Esquimalt, and upon arrival underwent a refit that lasted until June, 1945. She left Esquimalt July 4, 1945, for service with the British Pacific Fleet, arriving at Sydney, Australia on August 10. On August 31 Prince Robert entered Hong Kong, where her commanding officer had to honour re represent Canada at the surrender ceremonies, September 16. On October 20 she arrived at Esquimalt with repatriated Canadian prisoners from Hong Kong, and on December 10 was paid off and laid up in Lynn Creek, B.C. Sold in 1948, she became the merchant vessel Charlton Sovereign and, in 1952, the Italian-flag Lucania.