Construction of the RMS Mauretania II began on May 24th, 1937 at the Cammell Laird shipyard in Birkenhead, England. As the name implied, Mauretania II was to be a successor of the original Mauretania which, by the 1930's, was severely outdated and was scrapped in 1935. The Mauretania II was launched on July 28th, 1938 and left on her maiden voyage in the following year.

As with the Aquitania 25 years prior, Mauretania only experienced a briefest period of commercial operation before the outbreak of WWII and became a troop ship. After the war ended, she was sent into Gladstone Dock to be reconditioned by Cammell Laird & Co. for return to Cunard White Star service. After a complete overhaul and refurbishment of the interior, Mauretania made her first post-war Atlantic crossing to New York. Throughout the late 40's and into the 50's, Mauretania continued her trans-Atlantic service. In 1948 Mauretania was used to return home the Wright Brothers historic first aircraft, The Flyer of 1903, where it had been on loan to the Science Museum since 1928.

By the 1960's Mauretania was facing competition from more modern ships and was beginning to lose money for Cunard Line. She was converted to a cruise ship and painted pale green like the Caronia and took on a Mediterranean service calling at New York, Cannes, Genoa and Naples. It was an utter failure.

Mauretania left on her final voyage of a Mediterranean cruise on September 15th, 1965. She was to be withdrawn from service and sold to Ward's shipbreaking in Inverkeithing, Fife, Scotland. She left Southampton on November 20th, 1965 and arrived at her destination. By late April 1966, her funnels were gone, By mid-1966, the superstructure was removed, leaving only the keel of the ship. Scrapping was finished by late 1966.