The ship was protected by a main armored belt that was thick with a second layer of steel that was thick. The main deck was thick in the central area of the ship and reduced to in less critical areas. The main battery turrets were thick and the lower turret structure was housed in barbettes that were also 350 mm thick. The secondary turrets had 280 mm thick faces and the conning tower had thick sides. "Littorio" was fitted with a catapult on her stern and equipped with three IMAM Ro.43 reconnaissance float planes or Reggiane Re.2000 fighters.