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.
Otraria was one of two Argo-class submarines ordered by the Portuguese government, but taken over and completed for the Regia Marina during the 1930s. She played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
Balilla was the lead ship of her class of four 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.
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.
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.
Nereide 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.
Sirena 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.
Zaffiro 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 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.
Fratelli Bandiera was the lead ship of her class of four submarines built for the Regia Marina during the late 1920s.
Medusa 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.
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.
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.
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