After Calvi had been sunk, Finzi and Tazzoli were selected for conversion to "transport submarines" in order to exchange rare or irreplaceable trade goods with Japan.

During the sixth patrol from 7 to 29 December 1941 Calvi, Finzi and Tazzoli rescued sailors of the sunken raider Atlantis.

Admiral Karl Dönitz visited Giuseppe Finzi on 30 September to welcome Regia Marina sailors to the German base.

The third patrol near the British Isles from 24 October to 4 December 1940 revealed that the diesel engine air intake was too exposed for North Atlantic winter weather.

During the sixth patrol from 7 to 29 December 1941 Pietro Calvi, Giuseppe Finzi and Enrico Tazzoli rescued sailors of the sunken German commerce raider Atlantis.

On 26 November 1942 Giuseppe Finzi sailed for a ninth patrol to Brazil; but mechanical problems required return to base on 10 December.

Conversion to a transport submarine was never completed, and the boat was seized by the Germans on 9 September 1943 when Italy surrendered to the Allies.

Renamed UIT21 in German service, she was scuttled at Le Verdon-sur-Mer on 25 August 1944 to prevent her capture by the advancing Allied forces.

The boat sailed on 7 April 1941 to patrol between Freetown and the Azores; and shot down an attacking Bristol Blenheim while returning to port on 23 May.

During the seventh patrol from 7 to 27 December 1941 Pietro Calvi, Giuseppe Finzi and Tazzoli rescued sailors of the sunken German commerce raider Atlantis.

[9] After conversion to a transport submarine for blockade-running between Europe and the Far East, Enrico Tazzoli sailed for Japan on 16 May 1943 and was sunk by aircraft in the Bay of Biscay on 23 May.