The Argo-class was a class of two coastal submarines built by Cantieri Riuniti dell'Adriatico in Monfalcone for Portugal but operated by the Royal Italian Navy () after Portugal was unable to pay construction costs. The submarines were built in 1936, and both served in the Mediterranean Sea at the start of the Second World War. The boats were transferred to the BETASOM German submarine base at Bordeaux in 1940, but returned to the Mediterranean in 1941, where both were sunk within a few days of the September 1943 Italian armistice.