Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Effortless float
LowHigh
Dense, salty water — you float without effort.
SodiumChloruresBrome
Hateruma Onsen stands at the southern edge of Japan's inhabited world, on the country's southernmost island where the Milky Way arcs with exceptional clarity on moonless nights, earning Hateruma a reputation as Japan's finest stargazing destination. A monument marks the southernmost point of Japan, drawing travelers who wish to stand at the literal end of the archipelago while surrounded by turquoise waters and pure Pacific air. The onsen's warm geothermal waters offer restorative comfort after days of exploring an island where coral-fringed beaches stretch without crowds and the pace of life reflects the unhurried spirit of Okinawa's outermost communities.
Insider tip — Hateruma is Japan's southernmost inhabited island, just above the Tropic of Cancer, where the Southern Cross constellation is visible on clear nights — a rarity in Japan. The modest onsen facility uses sodium-chloride geothermal water appropriate to the island's coastal geology and is often enjoyed by cyclists who circle the 15-km perimeter road. The island's remoteness and lack of urban light make it one of Japan's premier stargazing destinations, and soaking under the stars is a highlight that draws visitors from across the country. Access is by high-speed ferry from Ishigaki, subject to sea conditions.
