When the Allies invaded Sicily on 10 July 1943, Arisio was still in command of the XII Corps located in western Sicily, which operated within the 6th Army of General Alfredo Guzzoni, but was only marginally involved in the initial fighting. On 12 July, only two days after the landings, Arisio was replaced by Francesco Zingales at the command of the XII Corps, and on 1 August he assumed command of the Seventh Army, replacing General Adalberto of Savoy-Genova, Duke of Bergamo. The army, which had its headquarters in Potenza, was composed of the XXXI Army Corps stationed in Calabria (General Camillo Mercalli), the XIX Corps stationed in Campania (General Riccardo Pentimalli) and the IX Corps stationed in Apulia (General Roberto Lerici). In early September his troops went into action against British forces, which had crossed the Strait of Messina and landed on the Calabrian coast in Operation Baytown. An early counterattack planned by the commander of the XXXI Army Corps, General Mercalli, aborted due to the retreat of the 29th Panzergrenadier Division of General Walter Fries who, obeying the orders of the Field Marshal Albert Kesselring, had moved to Castrovillari in order to cover the Gulf of Taranto from a possible Allied landing. Arisio immediately protested to the General Staff in Rome for Kesselring's behavior, but he was answered that German troops acted independently of Italian commands.