The MAS 555 was a motor torpedo boat (Motoscafo Armato Silurante) of the MAS 500 class whose purpose was to attack enemy ships, anti-submarine and escort operations. Built in 1941 with the others of the 3rd Series, it was armed with a single 20 mm/65 Breda cannon, two 450 mm torpedo launchers for surface targets, and six depth charges for enemy submarines. The MAS 555 was used both by the Regia Marina until 1943, and by the Italian Co-Belligerent Navy after the armistice, eventually to be sunk in the German landing at Rhodes, Greece in the same year.

Introduced in Update "Starfighters", the MAS 555 is an excellent torpedo boat capable of rapid attacks on enemy bluewater ships with torpedoes and depth charges, while the main armament consisting of a 20 mm Breda cannon is capable of causing good damage to enemy coastal boats. However, it can only survive a few hits from enemy ships and is also very vulnerable to attack from the air.