The flotilla operated mainly in the North Sea and against the Russian convoys (JW-, PQ-, QP- and RA series) in the Arctic Sea. The flotilla operated various marks of the Type VII U-boat until September 1944, when it had an influx of some Type IX boats from France. It also was the only flotilla to field the Type XXI U-boat for operational use, but the war ended before U-2511 saw action.