The Mediterranean
The first boats to enter the area were the U-97 and U-559 on 26 Sept, 1941. Any U-boat that entered the Mediterranean was lost forever to the Battle of the Atlantic as the currents in the Straits of Gibraltar were simply too strong to escape that way again while submerged (the only feasible way due to strong Allied ASW patrols in the Straits).
In this body of water the allies successfully tried a new ASW tactic called Swamp, see file on U-371 for more info.
The following 10 U-boats were lost at Toulon (see position of U-303) during July and August 1944, through allied air raids;
U-380,
U-410,
U-421,
U-466,
U-471,
U-586,
U-642,
U-952,
U-967 and
U-969.
The front is drawn as of July 1, 1943, just before the Allied (green) invasion of Siciley on 22 July. Borders are in their WWII state.
