Effective Naval Diplomacy: German–Italian Submarine Cooperation in the Atlantic, 1939–41

On 1 September 1940, the Italian Navy established the Command of the Atlantic Submarine Group in Bordeaux. Between that date and the signing of the armistice on 8 September 1943, 32 Italian submarines sank 109 ships, amounting to a total of 593,864 tons – representing 5.9 per cent of the successes achieved by U-boats in the Atlantic. While Italy’s overall contribution to the Battle of the Atlantic was peripheral, effective naval diplomacy between the two nations bolstered the Axis naval position, complicating Allied merchant shipping operations and causing significant, though not decisive, losses of personnel and equipment.