On 19 August, the submarine sighted a ship and commenced tracking, but she withheld her fire when her crew recognized the flag as Soviet (an ally of the United States at the time). "Wahoo" made for La Perouse Strait. The next day, she sighted a sampan and fired warning shots across the bow. When the sampan failed to stop, the submarine opened up on it with her 20 mm and four-inch guns. The sampan was soon a wreck. Six Japanese fishermen surrendered and were taken on board as prisoners of war. Eight hours later, "Wahoo" opened fire on two more sampans, enveloping them in flames. Members of the crews jumped overboard but showed no desire to be rescued. "Wahoo" completed the passage of Etorofu Strait, and then arrived at Midway on 25 August. She immediately got underway for Pearl Harbor, and she arrived there on 29 August.