'Adieu' was the Allied designation for the German surrender of U-boats at sea to Allied warships on or after VE-Day (8 May 1945).

On 5 May the U-boats in or near their operational areas in the Atlantic and off the coast of the UK were U-278, U-313, U-318, U-968, U-992 and U-1165 in the Arctic; U-287 and U-2336 in the North Sea; U-293, U-1105 and U-1305 to the west of the North Channel; U-825, U-956 and U-1023 in the Irish Sea; U-249 and U-776 in the English Channel; U-979 off Reykjavik; U-1009 in the North Atlantic as a weather boat; U-190, U-805 and U-889 off the east coast of Canada; U-530, U-853, U-858 and U-881 off the east coast of the USA; U-516 in the Bay of Biscay on a supply mission to the isolated garrison of St Nazaire in western France; U-2324 and U-2326 outbound to the North Sea; U-244, U-320, U-764, U-901, U-977, U-1010, U-1057, U-1058, U-1109, U-1272 and U-2511 outbound to the area west of the British Isles; U-485 and U-541 outbound to the Strait of Gibraltar; U-802, U-1228 and U-1231 outbound to the east coast of the USA; U-873 outbound to the Caribbean; U-963 outbound for a mining operation off Portland on the south coast of England; U-234 outbound to eastern Asia; U-255 inbound from France; U-2322 inbound from the North Sea; U-826 inbound from the North Atlantic; U-218 inbound from a mining operation in the Clyde river estuary; and U-510 and U-532 inbound from eastern Asia.

Most of the surrendered boats were later sunk in 'Deadlight'.