Soviet submarine A-3, previously called AG-25 and Marksist (Russian: Марксист, lit.

'Marxist'), was an American Holland-class submarine delivered to Russia just before the end of World War I and later commissioned into the Soviet Navy in 1922.

[1] A-3 became part of the Black Sea fleet of the Soviet Navy at the start of the Second World War.

The following day while the submarine was near Crimea she mistakenly fired two torpedoes at the wreck of the Soviet transport ship Fabritsius which had been sunk by a German bomber aircraft on 2 March 1942.

[2] Although the fate of the A-3 is still unsure, it is assumed that the submarine was sunk by depth charges on 28 October 1943 by the German auxiliary anti-submarine ship Shiff 19 at Karkinit Bay at 46°10′N 31°55′E / 46.167°N 31.917°E / 46.167; 31.917 with the loss of all 32 crew.