No. 52 · Yamanashi

Isawa Onsen

Isawa Onsen ranked No. 52 in the published 2025 Japan hot-spring destination list. Check bathing options, access and stay details before planning your visit.

Isawa Onsen hot-spring destination
Isawa Onsen, Yamanashi

Spring information

Water and bathing details for Isawa Onsen

Facility-level figures; blank town-wide averages are not inferred.

Named facility records for Isawa Onsen. Figures marked “Not published” are not treated as town-wide averages.

FacilitySpringSource dataSupplyBath type
Miyuki Onsen Ryokan (Day Use)Alkaline simple spring Source: The inn's naturally emerging Kan-juku-no-Yu system: Juku-no-Yu and Kan-no-YuSource temperature: Juku-no-Yu: 36.0°C; Kan-no-Yu: 50.8°C
pH: Not published in the current material checked; an older historical figure is not used as a current value
The springs emerge naturally on the property. The inn states that the baths are 100% free-flowing, with no recirculation, heating, added water or chlorine disinfection. Spring water is also used at the washing stations and showers.Ryokan. Choose Miyuki when the spring itself matters more than resort facilities. Its two naturally emerging sources, high flow rate and untreated free-flowing supply are unusually well documented; confirm day-use access before travelling.
Hotel Yamanami (Day Use)Alkaline simple spring (low-tonicity, alkaline, high-temperature spring) Source: Natural Isawa Onsen water; the current official pages do not identify the individual sourceSource temperature: Not published
pH: Not published
The hotel lists large baths, outdoor baths, Koshu wine baths and saunas. It does not publish water-addition, heating, recirculation and disinfection conditions for each bath, so the baths should not be described as uniformly free-flowing. The wine bath is a themed bath, not a separate natural spring.Ryokan. A practical choice if you are arriving by train, want a sauna or themed bath, or would rather soak into the evening. For a spring-first visit with documented untreated water, Miyuki Onsen has stronger evidence.
Hotel Fuji (Day Use)Alkaline simple spring Source: Natural Isawa Onsen water; the current hotel page does not name the individual sourceSource temperature: 41°C, listed by the hotel as spring temperature; this is not a fixed temperature for every bath
pH: Not published for this property; a pH value for the wider Isawa area is not substituted
The hotel lists hot-spring water in its large rock bath, garden bath and outdoor baths. It does not publish a complete bath-by-bath breakdown of water addition, heating, recirculation or disinfection, so the whole property should not be described as free-flowing.Ryokan. Pick Hotel Fuji if you want a large hotel bath and landscaped outdoor setting, and the short afternoon slot works for your itinerary. Bring or rent a bath towel; the face towel included with admission is not a substitute.

Destination comparison

What this onsen town offers

Popularity

81/100

History

69/100

Spring character

76/100

Town culture

70/100

Seasonal scenery

71/100

Access

71/100

Local history

How the town developed

Four seasons

Seasonal conditions and travel rhythm

SpringMar–May
Daytime range: 5–19°C
SummerJun–Aug
Daytime range: 24–32°C
AutumnSep–Nov
Daytime range: 14–25°C
WinterDec–Feb
Daytime range: 1–11°C

Plan your stay

Isawa Onsen: day trip or overnight?

Compare travel time, bath access and the time you want to spend in town.

Nearby destinations

Other places in the same prefecture in the published ranking.

Related guides

Guides to Isawa Onsen

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Official sources

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