Vettor Pisani was the lead ship of her class of four submarines built for the Regia Marina during the late 1920s. She was named after Vettor Pisani, a Venetian admiral. The submarine played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
Foca was the lead ship of her class of three submarine minelayers built for the Regia Marina during the late 1930s.
Atropo was one of three Foca-class submarine minelayers built for the Regia Marina during the late 1930s.
Zoea was one of three Foca-class submarine minelayers built for the Regia Marina during the late 1930s.
Diamante was one of a dozen Sirena-class submarines, the second sub-class of the 600 Series of coastal submarines built for the Regia Marina during the early 1930s.
Smeraldo was one of a dozen Sirena-class submarines, the second sub-class of the 600 Series of coastal submarines built for the Regia Marina during the early 1930s.
The Settembrini class was a pair of submarines built for the Regia Marina during the late 1920s. They played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
The Pisani-class submarines were built for the Regia Marina during the late 1920s. They played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
Luigi Settembrini was the lead ship of her class of two 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.
Reggio Settimo was one of two Settembrini-class submarines built for the Regia Marina during the early 1930s.
Argonauta was the lead ship of her class of seven submarines built for the Regia Marina during the early 1930s.
Salpa was one of seven Argonauta-class submarines built for the Regia Marina during the early 1930s.
Serpente was one of seven Argonauta-class submarines built for the Regia Marina during the early 1930s.
The Mameli-class submarine was one of the first classes of the submarines to be built for the Regia Marina after the First World War. Some of these boats played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists. Of the four boats built in this class, all but one survived the Second World War.
Pier Capponi was one of four Mameli-class submarines built for the Regia Marina during the 1920s.
Giovanni Da Procida was one of four Mameli-class submarines built for the Regia Marina during the 1920s. She played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
Goffredo Mameli was the lead ship of her class of four submarines built for the Regia Marina during the 1920s.
Des Geneys was one of four Pisani-class submarines built for the Regia Marina during the late 1920s. Due to her age, her usefulness was limited, and she saw no real service during World War II. The submarine was decommissioned in 1942 and converted into a battery-charging hulk.
Marcantonio Colonna was one of four Pisani-class submarines built for the Regia Marina during the late 1920s. Due to her age, her usefulness was limited, and she saw no real service during the war. The submarine was decommissioned in 1942 and scrapped the following year.
Giovanni Bausan was one of four Pisani-class submarines built for the Regia Marina during the late 1920s. Due to her age, her usefulness was limited, and she saw no real service during the war. The submarine was decommissioned in 1942 and converted into an oil barge.
Kingdom of Italy 
