7 Jan 1944
Aircraft attack, aircraft shot down: British Wellington HF245 (36 Sqdn RAF/Y, pilot F/O R.D. Bamford, RNZAF)

At 20.30 hours, the boat was attacked by the Wellington in the Mediterranean after it has passed the Strait of Gibraltar two days earlier. The aircraft made a low attack and dropped five depth charges that missed U-343 astern, but was in turn hit by AA fire in the port wing and caught fire. The Wellington was forced to ditch shortly thereafter, and the pilot and navigator were killed. The remaining four crewmen were picked up from their dinghy by ORP Slazak the next morning.

The sighting report of this aircraft led another Wellington HF221 (36 Sqdn RAF/M, pilot F/O J.T. Hutton) to the scene, which immediately attacked U-343 but its depth charges fell wide because the port engine had been hit by AA fire and the aircraft became difficult to handle, but managed to reach Bone and landed safely.

8 Jan 1944
Aircraft attack, aircraft shot down: British Wellington (179 Sqdn RAF/R, pilot F/O W.F.M. Davidson)

After the boat had fought off two aircraft attacks the day before, the Allies started a swamp operation and at 21.40 hours a Wellington (36 Sqdn RAF/B) located U-343 southwest of Cartagena which was then attacked by a Wellington (179 Sqdn RAF, pilot W/C J.H. Greswell, DFC) followed by another Wellington of the same squadron. The aircraft dropped six depth charges but several AA hits set the port wing on fire and the aircraft crashed into the sea, killing five crewmen. Only the pilot was thrown clear and rescued himself into a dinghy that was passed closely by the U-boat twice but the Germans did not take him prisoner because they had "more important things to do". He was picked up by HMS Active the next morning and later recieved the DFC.

The boat had already sustained damages in the attacks but there was still more to come because a Catalina (202 Sqdn RAF, pilot F/L J. Finch) joined the attack that lasted until 23.00 hours. AA fire damaged the port wing, fuselage and both fuel tanks of the Catalina and wounded the flight engineer, so the aircraft was forced to head for home. U-343, badly damaged and unable to dive, managed to escape in the darkness with only one crewman wounded by strafing and after repairs the boat safely reached her new base.

2 recorded attacks on this boat.