Before the outbreak of World War II, individual U-boat flotillas were under the direct command of a single
Führer der Unterseeboote (F.d.U.) in the person of
Karl Dönitz. who had also acted as commander of the
1st U-boat Flotilla. In 1939, Dönitz's title was renamed as the
Befehlshaber der Unterseeboote (B.d.U.) to which all the flotillas directly reported. The first U-boat region was created in Italy in November 1941 to provide local command authority for the U-boat flotillas operating in the
Mediterranean Sea. The largest region, "Region West" headquartered in Paris, was established in 1942 to oversee U-boat activity during the
Battle of the Atlantic. Later war U-boat regions were created between 1943 and 1944 due to the various operational needs of the U-boat flotillas. The standard rank for a U-boat region commander was either
Fregattenkapitän or
Kapitän zur See. Towards the end of the war, a new office known as
Kommandierender Admiral der Unterseeboote, was established by the
Kriegsmarine to direct overall submarine operations. An office known as the
Operationsabteilung (b.d.U.op) coordinated specific U-boat tactics. In the last weeks of the war, when U-boat operations were mostly restricted to the
North Sea around
Norway, the
Oberkommando der Marine (OKM) became the direct commander for the U-boat regions. Some flotillas overlapped between regions due to shifting base assignments and operational tasking. ==Atlantic U-boat regions==