Diane-class Submarine

Ships in class: 9

The 600 Series were seagoing submarines, though designated as coastal-type submarines, built for service in the Mediterranean. They were built to conform to the interwar naval treaties arising from the 1922 Washington and 1930 London conferences, which placed restrictions on the number and size of warships of various types that nations could build. The coastal submarine was limited to a 600-ton surface displacement, though there was no limit placed on the numbers of these vessels that could be built. During this period France was involved in a rivalry with Italy in the Mediterranean, leading to a naval arms race.

The French 600 series, and the later 630 series, was equivalent to the Italian 600 Series, the British S class, and the German Type VII U-boat.