Saikaidō Seamounts are an underwater feature in the Philippine Sea. The seamounts are in the northern end of the Kyushu-Palau Ridge (KPR). The seabed ridge begins in an area about 900 km from the eastern end of the or ""Bungo" strait" between the Japanese islands of Kyushu and Shikoku. The ridge creates a line on the ocean floor which runs southwest in the direction of the island of Palau. There is a chain of extinct volcanos on this line.