25 Aug 1942
At 02.42 hours, HNoMS Eglantine obtained a Radar contact when she approached the survivors of Trolla astern of convoy ONS-122 and had to leave them behind to investigate the contact, which proved to be U-256 that crash-dived when the area was illuminated with star shells. At 02.47 hours, the corvette attacked with depth charges but only dropped one because both throwers misfired and the trap jammed. Nevertheless it was very accurate and a leak in an exhaust pipe caused the stern heavy U-256 to fell to a depth of about 200 meters. The corvette made two more attacks with eight and ten depth charges, but then had to return to the convoy at 02.58 hours. The U-boat managed to surface about 30 minutes later and had to abort the patrol due to the damage sustained. (Sources: ADM reports, KTB U-256)

2 Sep 1942
Aircraft attack, aircraft shot down:British Whitley Z9515 (77 Sqdn RAF/H, pilot P/O A. Cassie)

At 08.30 hours, the inbound boat was attacked by the Whitley (misidentified as Wellington) in the Bay of Biscay. The aircraft strafed the boat and dropped 2 or 3 bombs that fell about 15 metres astern. The Germans observed AA hits in the cockpit area and saw the Whitley flying away very low with a smoke trail. Its crew sent a SOS and probably ditched, but the 5 men crew was lost. U-256 was badly damaged in the attack and limped into Lorient the next day, some damage found on deck were apparently caused by the propeller of the aircraft.

8 Oct 1943
At 03.34 hours, the outbound boat was attacked by the Leigh Light equipped British Wellington aircraft HF190 (612 Sqdn RAF/J, pilot P/O M.H. Paynter, RAAF) in the Bay of Biscay. U-256 was not damaged by the straddle of 6 depth charges and escaped by crash-diving. AA fire had hit the starboard elevator and the rear turret of the aircraft but it returned safely to base. (Sources: Franks/Zimmerman)

16 Nov 1943
At 02.08 hours the inbound boat encoutered a Halifax Mk.II aircraft (502 Sqdn RAF/D, pilot F/O F.T. Culling-Mannix, RNZAF) in the Bay of Biscay. The aircraft passed about 200 metres behind U-256, was damaged by AA fire at the starboard wing tip and turned away. When the Halifax returned to the area the U-boat already escaped by crash-diving. (Sources: Franks/Zimmerman)

11 Mar 1944
Aircraft attack, aircraft shot down: Canadian Wellington HF311 (407 Sqdn RCAF/H, pilot P/O E.M. O’Donnell)

At 21.48 hours, the boat witnessed an aircraft crashing into the sea close to her. The Germans had not fired at the aircraft, which apparently crashed on its own during preparations for the low attack run. All six crewmen were lost.

19 Mar 1944
Aircraft attack, aircraft shot down: British Liberator (224 Sqdn RAF/F, pilot F/L R. Dunn)

At 23.12 hours, the inbound boat was illuminated by Leigh Light and strafed by the Liberator in the Bay of Biscay. The Germans observed hits in the right wing from the 20mm AA guns and the fuselage from the 37mm AA gun. Flames were seen coming from the bomb bay and one of the engines when the aircraft passed at the height of 50 meters behind U-256, dropped six depth charges and crashed into the sea 500 meters away, killing all 10 crewmen. The boat was not damaged in the attack.

7 Jun 1944
Aircraft attack, aircraft shot down:British B-24 Liberator (Sqdn 224/M).

7 recorded attacks on this boat.