"Thresher" next set course for the Luzon Strait, between Batan Island and Luzon, in the Philippines. At 11:43 on 15 January, she came to the surface and spotted a Japanese aircraft carrier with an escorting destroyer soon thereafter. The boat submerged to periscope depth in time to observe two enemy destroyers rapidly approaching. With insufficient time to maneuver for a "down the throat" shot, "Thresher" went deep and rigged for silent running. The destroyer churned overhead and dropped four depth charges, none close. After remaining overhead two hours, dropping between ten and fifteen more depth charges, the enemy finally turned away, leaving "Thresher" unscathed.