Favourable reports of the type's reliability and performance during the Spanish Civil War led to the 1938 Kingdom of Yugoslavia's order of 45 aircraft generally similar to the SM.79-I variant, designated the SM.79K. They were delivered to Yugoslavia in 1939, but most were destroyed during the 1941 Axis invasion by their crews or by advancing Axis forces. During several sorties against German and Italian forces they managed some success in Kačanik Gorge. Some of these aircraft escaped to Greece, carrying King Peter Karadjordjevic and his entourage. A few survived, one to be pressed into service with the pro-Axis forces of the NDH, and four which became AX702-AX705 in the RAF.