U-boat deployment in the Far East had been reviewed since 1941. However, serious technical and logistic difficulties were encountered. Also, it was considered as an unnecessary diversion from the North Atlantic Tonnage War.
In the second half of 1942 the first wave of boats was sent to the Cape Town area. This was later continued but U-boats always came back to Europe at that time.
From May 1943 onwards a complicated programme of the Italian transports, Japanese movements and so-called Monsun U-boats was carried out. Unlike previous U-boats operating in the Indian Ocean, Monsun boats were to be stationed in the Far East bases provided by the Japanese. Gradually the effort moved from combat missions to transport missions. However, only 4 U-boats out of 14 stationed ever in the Far East managed to reach back Europe.
Mainly German U-boats are described here. Italian submarine transports (so-called Merkator boats) were assigned mainly to transport duties and carried stores for the Monsun bases in the Far East.