Ōshima Onsen

Ōshima Onsen is a unique hot spring on Izu Oshima island, the largest of the Izu Islands in Tokyo Metropolis, formed through a remarkable process in which the underground water temperature of the island's wells gradually rose following the containment of the 1986 eruption of Mount Mihara, the island's active central volcano, eventually qualifying as a certified hot spring source from water that was originally drawn as ordinary well water. Izu Oshima, easily accessible by high-speed ferry from Tokyo or by flight, is famous for the consistently active Mihara volcano whose eruptions have repeatedly reshaped the island's landscape, and for the remarkable tradition of camellia cultivation that makes the island's hillsides spectacular with red and pink blooms each winter and spring. The sulfurous hot spring that emerged from the post-eruption thermal warming of Oshima's subsurface provides a distinctive bathing connection to the island's volcanic identity, allowing visitors to experience the geothermal heritage of one of Tokyo's volcanic island territories in the warm embrace of Mihara's subterranean heat.