The I-351-class submarine was a class of tanker/transport submarines built for the Imperial Japanese Navy (IJN) during World War II. The IJN called this type of submarine Senho type submarine . The type name, was shortened to Hokyū Sensuikan . The IJN designed these submarines to support flying boats in forward areas. By the time the first submarine was finished, this capability was no longer needed and she was converted into a tanker. That boat, I-351, was sunk on the return leg of her second voyage in 1945; the second boat, I-352, was destroyed by an American air raid before she was completed. Four additional submarines were planned, but were cancelled before they were laid down.