"Picuda" put to sea from Midway with the wolf-pack 4 May to conduct her second war patrol in waters off Formosa. On 22 May, she sent four bow shots streaking to sink 1200-ton river gunboat "Hashidate". She also severely damaged 3172-ton cargo ship "Tsukauba Maru" with the same salvo. The latter enemy was polished off by land-based aircraft from the United States Army Air Corps the following day. On 2 June, "Picuda" closed a convoy of twelve ships hugging the coast of Formosa. After sending her contact report to the other submarines of her wolf-pack, she slipped between two of the three leading escorts and pressed home an attack on a large tanker. Three hits were heard as all escorts made for "Picuda". She skillfully maneuvered clear and sustained no damage from the many depth charges which exploded on all sides and above from eight enemy vessels during the next hour. She continued to patrol the Formosa coast until 4 June then passed off Batan Island and eastward of the Nansei Shoto to a point northward of Chichi Jima by 14 June. Two days later she pointed her bow for Midway where she arrived 22 June. She put to sea the next day to arrive at Pearl Harbor 27 June. After the end of the second war patrol, Raborn was replaced as skipper of "Picuda" by Commander Glynn R. Donaho.