The first units equipped were No.141 Sqn., Eritrea, No.83 Group, Augusta, No.85, Elmas, and No.62, Spain (for operations). By the time Italy entered World War II on 10 June 1940, 202 aircraft were in service in 15 squadrons. They were used by 20 Sqn. and patrolled the Mediterranean, as well as performing air-sea rescue operations. During the short campaign against France, seven Z.501s were destroyed by a French attack on their base in Sardinia. Another crashed the next day. In July, encounters with Royal Navy Fleet Air Arm fighters and accidents claimed many Z.501s, with a total of 11 destroyed in action, while the number that were operational dropped to 77. The Z.501 operated in all theatres and 62 aircraft were lost in 1940, leaving 126, of which only 87 were operational. New orders were placed with the manufacturer Aeronautica Sicula.