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.
The Glauco class was a pair of submarines ordered by the Portuguese government, but were taken over and completed for the Regia Marina during the 1930s. They played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
The Foca class were a group of three minelaying submarines built for the Regia Marina during the 1930s. All three sister ships played minor roles during the Second World War. One was lost to unknown causes while trying to lay a minefield off British Palestine in 1940, but the other two survived the war to be discarded in 1947.
Balilla was the lead ship of her class of four submarines built for the Regia Marina during the late 1920s.
Antonio Sciesa was one of four Balilla-class submarines built for the Regia Marina during the late 1920s. She 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.
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.
Luciano Manara was one of four Bandiera-class submarines built for the Regia Marina during the late 1920s. Completed in 1929,
Serpente was one of seven Argonauta-class submarines built for the Regia Marina during the early 1930s.
Pier Capponi was one of four Mameli-class submarines built for the Regia Marina during the 1920s.
Tito Speri was one of four Mameli-class 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.
Tricheco 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 1942 by the British submarine HMS Upholder.
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.
Filippo Corridoni was one of two Bragadin-class submarines built for the Regia Marina during the late 1920s. The boat participated in the Second World War and was discarded in 1948.
Italy
