When Yugoslavia entered World War II due to the German-led Axis invasion of the country in April 1941, both boats were captured by Italian forces, after an abortive attempt by one crew to join the fledgling Navy of the Independent State of Croatia. They were commissioned in the Italian Royal Navy and operated with a squadron out of the Dalmatian port of Šibenik, where they had been based pre-war. Their age and condition meant they were only used for patrolling and second-line duties. The first boat sank near the Dalmatian island of Mljet in July 1942 when its hull failed. The second one became non-operational in September 1943, and soon after Italy capitulated her crew escaped and sailed to Taranto in Allied-occupied southern Italy. This surviving boat was broken up there after the war.