Sado (佐渡) was one of fourteen Etorofu-class coastal defense ships built for the Imperial Japanese Navy during World War II. She was first launched at the end of November 1942.
After escorting the convoy for three years. At the last convoy, the convoy was attacked by USS Rasher and USS Spadefish. He was torpedoed and sank on August 22, 1944 one hour after Matsuwa sank.