During the Allied landings in North Africa British airborne units landed in Tunisia, which included the 1st Para Brigade, which was detached from the rest of the division and now commanded by Brigadier Edwin Flavell. At this time Frost, who was now an acting lieutenant-colonel and in command of his battalion, was tasked to attack enemy airfields near Depienne 30 miles south of Tunis. The airfields were found to be abandoned and the armour column they were supposed to meet up with at Oudna never arrived, leaving Frost's battalion 50 miles behind enemy lines. Heavily outnumbered and continuously attacked on their route out, they managed to fight their way back to Allied lines but lost 16 officers and 250 men. The battalion carried on fighting with the British First Army through to Tunis. For this action he was awarded his first Distinguished Service Order (DSO) on 11 February 1943.