HMS Caroline became a depot ship to an anti-submarine striking force of patrol vessels during World War Two. With the fall of France in 1940 this force was reinforced and soon increased to 70 vessels. Caroline provided signal and cypher facilities to her attached light craft and as the war developed Belfast soon came to play a vital part in the Battle of the Atlantic.

At the end of World War Two Caroline was once again paid off into the Ulster Division of the Royal Navy reserve until 2009. At the time of her decommissioning in 2011 she was the second-oldest ship in Royal Navy service.

Park Hood were commissioned to landscape around HMS Caroline.