The ship saw extensive action during World War II, including the battles of Cape Spartivento and Cape Matapan in November 1940 and March 1941, respectively. "Trieste" was also employed to escort convoys to supply Italian forces in North Africa; during one of these operations in November 1941, she was torpedoed by a British submarine. On 10 April 1943, while the ship was moored in La Maddalena, Sardinia, she was bombed and sunk by American heavy bombers. Her superstructure was cut away and she was refloated in 1950; the Spanish Navy purchased the hull in 1952, with plans to convert the vessel into a light aircraft carrier, though the plan came to nothing due to the growing costs of the project. She was ultimately broken up by 1959.