U 124 was a German U-Boat Type IX B, which was used during the Second World War by the German navy. 

It was one of the most successful U-boats.

During the attacks on Allied ships in the convoy OS-45, the corvette HMS Stonecrop and the sloop HMS Black Swan in turn attacked U-124 with depth charges and sank it on 2 April 1943 west of Porto, Portugal, at the position 41 ° 0 2 'N, 15 ° 39' W in naval grid square CF 3922ND. 

All 53 crew members were killed.