Heda Onsen

Numazu, Shizuoka, Japan

Location: Numazu, Shizuoka, Japan
Water type: sodium chloride
Temperature: 41 °C
pH: 7.3

Water profile

Thermicity

Sedative

41 °C

LowHigh

Relaxing — deep, immediate muscle release.

Mineralisation

Restorative

LowHigh

Loaded with major ions — the essential minerals (Ca, Mg).

Buoyancy

Effortless float

LowHigh

Dense, salty water — you float without effort.

SodiumChloruresBrome

Heda Onsen is located in the remote fishing village of Heda on the Izu Peninsula in Shizuoka Prefecture, a place already woven into the fabric of Japanese-Russian diplomatic history through the construction of the schooner Heda in 1855, built jointly by Japanese craftsmen and Russian sailors after the warship Diana was destroyed by a tsunami, and the thermal spring here adds geothermal depth to this historically layered coastal setting. The spring's iodine-rich thermal waters reflect the volcanic geology of the Izu Peninsula, a geologically young volcanic arc that remains one of the most seismically and geothermally active regions in the Japanese archipelago. Heda Onsen invites visitors to combine the historical maritime heritage of this remote Izu village with the deeply restorative pleasure of bathing in naturally iodine-bearing spring water drawn from the same volcanic earth that has shaped the dramatic coastal landscape of western Izu for thousands of years.

Insider tip — Heda Onsen is a coastal retreat on the Izu Peninsula in Shizuoka Prefecture, where iodine and sodium-chloride waters emerge near one of Japan's most scenic bays. The spring-fed baths have a warming, deeply penetrating quality that soothes joints and promotes circulation, particularly valued by fishermen returning from long sea voyages. Views of Mount Fuji across Suruga Bay on clear winter mornings are simply breathtaking. The small port village atmosphere adds a charming, unhurried authenticity to the bathing experience.

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