The story of Italy’s Decima MAS (Decima Mezzi d’Assalto, or 10th Assault Vehicle Flotilla), is a peculiar tale regarding Axis Special Forces in World War II. On one hand they were the best combat frogmen produced by any nation during the conflict. On the other, the courage and innovation they brought to the history of naval warfare became stained by an evil ideology that drove many of them to commit atrocities, not at sea, but on land, after Italy toppled Mussolini and the unit split apart upon deciding where their allegiances lay. This article will focus on how the unit originated, its most storied missions, and how ‘X MAS,’ as it was nicknamed, ultimately met a silent end.

Seeds of this unit began with Italian spearfishing in the Mediterranean in the 1920s and 30s. During this time, the sport evolved from free diving to snorkeling to using rebreathers, which introduced scuba diving to the area and garnered the interest of the Italian navy (Regina Marina). The Italians created their first Special Forces frogman unit, known as the 1st Assault Vehicle Flotilla, around the new equipment in 1939.

Utilizing the ideas of two naval combat engineers, Majors Elios Toschi and Teseo Tesei, the Flotilla, under Commander Paolo Aloisi, began creating tactics based around not only scuba gear, but motor boats and a vehicle unique to the Italian navy, one that was fated to be copied in one form or another all the way down to the present day Swimmer Delivery Vehicle (SDV): The manned torpedo. This versatile two-man craft, known affectionately as ‘Maiale’ (pig), was destined to play a key role in the majority of successes enjoyed by the frogmen.

After Mussolini declared war against Great Britain, Italy joined Germany’s side on June 10, 1940. The next few months saw Italian forces trying to match, without much success, the prowess of their ally, and this included X MAS, which found all of its missions starting from an August 22 attempt against the harbor in Alexandria, Egypt to an October 21st attempt at Gibraltar, ending in failure or cancellation. The closest they got to sinking a ship was when a single Maiali brought its crew under the battleship HMS Barham. Charges were placed but caused little damage. Despite this, lessons were learned from every failure and, when 1941 arrived, X MAS was ready to shine among the rest of Italy’s bumbling military.