The Gruppe Monsun or Monsoon Group was a force of German U-boats (submarines) that operated in the Pacific and Indian Oceans during World War II. Although similar naming conventions were used for temporary groupings of submarines in the Atlantic, the longer duration of Indian Ocean patrols caused the name to be permanently associated with the relatively small number of U-boats operating out of Penang (primarily its capital, George Town).[1] After 1944, the U-boats of the Monsun Gruppe were operationally placed under the authority of the Southeast Asia U-boat Region.
The Indian Ocean was the only place where German and Japanese forces fought in the same theatre. To avoid incidents between Germans and Japanese, attacks on other submarines were strictly forbidden.[2] Altogether 41 U-boats of all types including transports would be sent; a large number of these, however, were lost and only a small fraction returned to Europe.[3][4]