Decima MAS was active during the Battle of the Mediterranean and took part in a number of daring raids on Allied shipping. These operations involved surface speedboats (such as the Sinking of HMS "York"), manned torpedoes (the Raid on Alexandria) and "Gamma" frogmen (against ). During the campaign Decima MAS took part in more than a dozen operations which sank or damaged five warships (totalling 72,000 Gross Register Tonnage) and 20 merchant ships (totalling 130,000 GRT).