The Italian Ala Littoria, Belgian S.A.B.E.N.A., and Czechoslovakian C.S.A. airlines were supplied with the SM.73 in the mid to late 1930s.
When Italy entered World War II the Commando Servizi Aerei Speciali (C.S.A.S.) took over the Ala Littoria's SM.73.
Thirteen were assigned to the 605a and 606a Squadriglie of the 148° Gruppo "T" at Reggio Calabria. They transported many supplies and troops to North America.