Comandante Faà di Bruno, also referred to by its shortened name Faà di Bruno, was a Marcello-class submarine built for the Royal Italian Navy in the 1930s. It was sunk in 1940 by British and Canadian destroyers escorting a convoy.
The Italian submarine Flutto was the name ship of her class of submarines built for the Royal Italian Navy during World War II. She obtained no successes during her short career, and was sunk by British ships during the Invasion of Sicily in 1943.
Domenico Millelire was one of four Balilla-class submarines built for the Regia Marina during the late 1920s.
Argo was the lead ship of her class of two submarines ordered by the Portuguese government, but taken over and completed for the Regia Marina during the 1930s.
Velella was one of a pair of submarines ordered by the Portuguese government, but taken over and completed for the Regia Marina during the 1930s.
Galatea 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. She played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
Naiade 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.
Rubino 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 Bandiera-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.
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.
Salpa 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.
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.
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.
Italy 
