Kutsuno Onsen

Iiyama, Nagano, Japan

Location: Iiyama, Nagano, Japan
Water type: thermal
Temperature: 40 °C
pH: 7.3

Water profile

Thermicity

Sedative

40 °C

LowHigh

Relaxing — deep, immediate muscle release.

Mineralisation

Balancing

LowHigh

Rich in trace elements — gentle on the skin.

Buoyancy

Standard buoyancy

LowHigh

Soft water — natural, classic buoyancy.

BicarbonatesCalcium

Kutsuno Onsen in Nagano Prefecture flows with simple thermal waters in a prefectural landscape of extraordinary geothermal richness, where the volcanic geology of the Japanese Alps and the Fossa Magna geological zone produces thermal springs of remarkable variety across dozens of highland valleys and mountain communities throughout the prefecture. The name Kutsuno, suggesting a hollowed or carved-out place where water gathers, evokes the geological character of a spring emerging from a carved rock basin or natural depression in the mountain terrain, a naming convention that embeds the spring's identity in the specific topographic feature of its source. Kutsuno Onsen contributes to Nagano's extraordinary thermal diversity with its simply mineralized waters, offering visitors the gentle, meditative pleasures of natural hot spring bathing in a prefectural landscape where the tradition of mountain onsen has been an inseparable part of community life for as long as the volcanic earth has been releasing its geothermal warmth.

Insider tip — Kutsuno Onsen nestles in the Nakatsu River valley of northern Nagano, surrounded by the dramatic peaks of the Northern Alps and renowned for deep powder skiing in winter. The simple thermal waters provide a warm contrast to the heavy snowfalls that blanket the area from December through March. The local inn serves hearty mountain cuisine featuring wild mushrooms, river fish, and locally made sake. Dawn bathing in the outdoor pools, with snow-capped peaks glowing pink at sunrise, is an experience few visitors forget.

Find hotels nearby →Tickets & activities →See the map & practical info →