"I-401" and "Segundo" arrived in Sagami Bay on the coast of Honshu at 05:00 on 31 August 1945. The American flag was raised on "I-401", and Nambu presented the officer commanding the prize crew with two "katana" as a symbol of surrender. Later in the day, a new prize crew from the submarine tender came aboard "I-401" and relieved the "Segundo" prize crew, after which "I-401" proceeded to Yokosuka and tied up along with "I-14" near "Proteus" and twelve U.S. Navy submarines chosen to represent the U.S. Navy Submarine Force at the Japanese surrender ceremony in Tokyo Bay. At 08:00 on 1 September 1945, Imperial Japanese Navy battle flag was lowered, and during the surrender ceremony on 2 September 1945, the Commander, Submarine Force, U.S. Pacific Fleet (COMSUBPAC), Vice Admiral Charles A. Lockwood, ordered his personal flag hoisted aboard "I-401".