The MAS 561 was a motor torpedo boat (Motoscafo Armato Silurante) of the MAS 500 class, whose purpose was to attack enemy ships as well as perform anti-submarine and escort operations. Built in 1941 alongside the others of the 3rd Series, the MAS 561 in particular was captured during the 1943 Italian armistice by the RSI (Italian Social Republic) and modified to add two 12.7 mm Breda-SAFAT single-mount machine guns to increase its effectiveness against Allied boats and to serve as anti-aircraft defence against enemy aircraft. Eventually, it was taken by the Germans and sank with its entire crew on 23 April 1945.

Introduced in Update "Raining Fire", the MAS 561 replaced the old reserve boat (MAS 555). It is the first Italian coastal ship you will play, and thanks to its speed, you will be able to approach enemy ships quickly and launch torpedoes or depth charges, causing serious damage or outright destruction. The armament consists of two 12.7 mm and one 20 mm guns, giving it good firepower against coastal boats. However, it is very fragile against enemy fire, having little armour and a small crew.