Sagami Bay (相模湾, Sagami-wan, also known as the Sagami Gulf or Sagami Sea) lies south of Kanagawa Prefecture in Honshu, central Japan, contained within the scope of the Miura Peninsula, in Kanagawa, to the east, the Izu Peninsula, in Shizuoka Prefecture, to the west, and the Shōnan coastline to the north, while the island of Izu Ōshima marks the southern extent of the bay. It lies approximately 40 kilometres (25 mi) southwest of the capital, Tokyo.