The Trento class was a group of two heavy cruisers built for the Italian Regia Marina in the late 1920s, the first such vessels built for the Italian fleet. The two ships in the class—Trento and Trieste, were named after the redeemed cities of Trento and Trieste annexed from the Austro-Hungarian empire after the victory in World War I. The ships were very lightly armored, with only a 70 mm (2.8 in) thick armored belt, though they possessed a high speed and heavy main battery of eight 203 mm (8 in) guns. Nominally built under the restrictions of the Washington Naval Treaty, the two cruisers nevertheless exceeded the displacement limits imposed by the treaty.
Enrico Toti was one of four Balilla-class submarines built for the Regia Marina during the late 1920s. The boat played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists. She was the only Italian submarine to have sunk a Royal Navy submarine during the Second World War.
Giuseppe Garibaldi was an Italian Duca degli Abruzzi-class light cruiser, that served in the Regia Marina during World War II. After the war she was retained by the Marina Militare and upgraded. She was built by CRDA, in Stabilimento Tecnico Triestino shipyard Trieste and named after the Italian general Giuseppe Garibaldi.
The Balilla class were the first submarines to be built for the Italian navy following the end of World War I. They were large ocean-going cruiser submarines designed to operate in the Indian Ocean based in Italy's East African colonies. The design was double-hulled and based on the German Type UE 2 U-boats, one of which, U-120 was supplied to the Italians as a war reparation. A 425 horsepower (317 kW) auxiliary diesel engine was installed as an extra generator.
Leonardo da Vinci was a Marconi-class submarine of the Italian navy during World War II. It operated in the Atlantic from September 1940 until its loss in May 1943, and became the top scoring non-German submarine of the entire war.
Fiume was a Zara-class heavy cruiser of the Italian Regia Marina, named after the Italian city of Fiume, she was the second of four ships in the class, and was built between April 1929 and November 1931. Armed with a main battery of eight 8-inch (200 mm) guns, she was nominally within the 10,000-long-ton (10,000 t) limit imposed by the Washington Naval Treaty, though in reality she significantly exceeded this figure.
The Piaggio P.8 was an Italian reconnaissance floatplane designed and built by Piaggio for the Regia Marina.
The Macchi M.53 was an Italian reconnaissance floatplane designed and built in the late 1920s by Macchi for the Regia Marina.
The Acciaio-class submarine was the fifth subclass of the 600 Series of coastal submarines built by the Regia Marina. They were completed during the early 1940s and saw service in World War II.
The Liuzzi class was a class of four submarines built by Tosi in Taranto for the Royal Italian Navy. The submarines were built in 1939 and began their Second World War service in the Mediterranean Sea, where Liuzzi was sunk. The three surviving boats were transferred to the BETASOM Atlantic submarine base at Bordeaux in 1940. After Tarantini was sunk, Bagnolini and Giuliani were selected for conversion to "transport submarines" in order to exchange rare or irreplaceable trade goods with Japan. Cargo capacity of 160 tons reduced reserve buoyancy from between 20 and 25% to between 3.5 and 6%; and armament was reduced to defensive machine guns. The submarines saw action in the Second World War during which they collectively sunk 5 freighters and 1 light cruiser and were eventually either sunk or captured.
Delfino was one of four Squalo-class submarines built for the Regia Marina during the late 1920s. The boat served in World War II and was sunk in 1943 after a collision with another Italian ship.
Giuseppe Finzi was one of three Calvi-class submarines built for the Regia Marina during the 1930s. Completed in 1936, she played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists. The submarine made multiple patrols in the Atlantic Ocean during the Second World War, sinking five Allied ships. Gisueppe Finzi began conversion into a transport submarine in 1943, but was captured by the Germans in September 1943 before it was completed and redesignated as UIT-21. She was scuttled by them in August 1944 to prevent her capture.
Romolo Polacchini was an Italian admiral during World War II.
Mario Arillo was an Italian naval officer during World War II.
Italian submarine Neghelli was an Adua-class submarine built for the Royal Italian Navy during the 1930s. It was named after a town of Negele in Ethiopia.
Italian submarine Malachite was a Perla-class submarine built for the Royal Italian Navy during the 1930s. She was named after a gemstone Malachite.
Ametista was the lead ship of her class of a dozen submarines, the second sub-class of the 600 Series of coastal submarines built for the Regia Marina during the early 1930s.
Jantina was one of seven Argonauta-class submarines built for the Regia Marina during the early 1930s. She played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists, and was later sunk during World War II.
The Bragadin-class submarines were built for the Regia Marina during the late 1920s. Both boats participated in the Second World War and were discarded in 1948.
The Quarta Flottiglia MAS was an Italian flotilla of the Regia Marina created during the Fascist regime.
Kingdom of Italy 
