 The submarines investigated Rossel Island and the Deboyne Group anchorage in the Louisiade Archipelago, Jomard Channel, and the route to Port Moresby from the east.They did not sight any Allied ships in the area and returned to Rabaul on 23 and 24 April respectively.The Japanese Port Moresby Invasion Force, commanded by Rear Admiral Kōsō Abe, included 11 transport ships carrying about 5,000 soldiers from the IJA's South Seas Detachment plus approximately 500 troops from the 3rd Kure Special Naval Landing Force (SNLF).