Izu Ōshima is an inhabited volcanic island in the Izu archipelago in the Philippine Sea, off the coast of Honshu, Japan, 22 km east of the Izu Peninsula and 36 km southwest of Bōsō Peninsula. As with the other islands in the Izu Island group, Izu Ōshima forms part of the Fuji-Hakone-Izu National Park.