[2] On 27 March 1942 the German Kriegsmarine naval staff requested that the Imperial Navy launch operations against Allied convoys in the Indian Ocean, and on 8 April the Japanese agreed to dispatch a detachment of submarines to the East Coast of Africa.

Two days later she sailed from Penang accompanied by the auxiliary cruiser and supply ship Aikoku Maru to reconnoitre selected points on the East African coast.

On 2 August she arrived in the Bay of Biscay and was escorted into Lorient by a powerful force of German M-class minesweepers and Luftwaffe Junkers Ju 88 bombers.

[2] The officers and crew of I-30 were greeted by Grossadmiral Erich Raeder, Admiral Karl Dönitz, and Captain Yokoi Tadao, the Japanese Naval Attaché to Germany.

The officers and crew of I-30 were feted by their German allies, travelling to Berlin where Commander Endo was presented to Adolf Hitler, and returning to Lorient via a sightseeing trip to Paris.

101 Navy Repair Unit recovered some of her cargo, including most of the 20 mm guns, torpedo data computers, and the radar blueprints, though they were found to be unusable after their immersion in salt water.