Seven Belgian S.73s were flown to the United Kingdom in May 1940 and were pressed into service by the Royal Air Force, and, operated by the SABENA flight crews, were used to fly ammunition to the British Expeditionary Force in Northern France. After two were destroyed by the Luftwaffe at Merville on 23 May, SABENA ordered its surviving aircraft, including the five S.73s, to move to France in preparation for transfer to the Belgian Congo. After the surrender of Belgium on 28 May the SABENA fleet was placed at the disposal of the French government and used to ferry pilots between the French mainland and French North Africa. Following France's surrender on 22 June 1940, the SABENA fleet, including the S.73s, was seized by Italy and operated by the "Regia Aeronautica". The S.73s still in Italy were used to equip 605 and 606 "Squadriglie". Four S.73s survived until the 1943 armistice, three being used by the Allies and one by the pro-Axis government; all had been taken out of service by the end of the war.