After work up trials in Holy Loch, Unbroken went out to join the 10th Flotilla at Malta, with a work-up patrol from Gibraltar.

She landed saboteurs under the command of Captain Peter Churchill at Antibes in the south of France.

She was badly damaged in October 1942, by a counter-attack by Italian escorts after hitting a tanker, and was again repaired at Malta.

Bolzano was hit in her oil tanks and set ablaze; she had to be beached at Panarea island; the Attendolo lost sixty feet of bow.

Unbroken was transferred on loan to the Soviet Union on 26 June 1944, where she was renamed V-2 (Cyrillic: В-2).