Yunohama Roten Onsen
Oshima Island, Tokyo, Japan
Illustration photo — not a verified picture of this exact spot.
- Location
- Oshima Island, Tokyo, Japan
- Water type
- sulfurous
- Temperature
- 44 °C
- pH
- 6.5
Water profile
Thermicity
Sedative
LowHigh
Relaxing — deep, immediate muscle release.
Mineralisation
Bio-active
LowHigh
Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
SoufreSulfuresSulfates
Yunohama Roten Onsen is set on Oshima Island, off the coast of Tokyo, a volcanic island known for its geothermal activity. Sulfurous water rises at 44°C, feeding an indoor bath and an ocean-facing rotenburo, with a sauna also on site.
Insider tip — Yunohama Roten Onsen is an outdoor rocky-shore bath on Izu Oshima, a volcanic island in the Philippine Sea administered by Tokyo, where active Mount Mihara fuels a vigorous sulfurous spring. The roten, open-air bath, sits directly above the ocean surf line, creating a dramatic juxtaposition of hot sulfurous mineral water and cold Pacific spray. Access requires a ferry from Tokyo port, which filters the crowd to those genuinely seeking a wild geothermal experience. Sunrise soaks when the Fuji silhouette appears on the western horizon are legendary among enthusiasts.
Nearby
Frequently asked questions
How hot is the water?
The water runs quite hot here, around 44 °C — a sedative water that brings immediate muscle release.
What type of water is found here?
This spot features sulfurous water.
What is the best season to visit?
The most favourable period for this spot is: Toute l'année (idéal automne-hiver).