No. 1 · Gunma

Kusatsu Onsen

Kusatsu Onsen ranked No. 1 in the published 2025 Japan hot-spring destination list. Check bathing options, access and stay details before planning your visit.

Kusatsu Onsen hot-spring destination
Kusatsu Onsen, Gunma

Spring information

Water and bathing details for Kusatsu Onsen

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

Kusatsu’s public baths and inns draw from different local sources. The figures below describe the named facility or source, not every bath in town.

FacilitySpringSource dataSupplyBath type
NarayaShirahata source; acidic sulfur–aluminium–sulfate–chloride springSource temperature: 55–56°C at the source; cooled to 46–47°C overnight before distribution
pH: Not published on the cited page
The inn lets the water cool naturally, holds it in two tanks overnight, then feeds the baths continuously as free-flowing spring water. It adjusts flow by weather to keep the baths around 41–42°C.Separate men’s and women’s public baths with indoor and outdoor pools; three private open-air baths are also listed.
OhtakinoyuNikawa source; acidic sulfur springSource temperature: Not published; the official page describes it as a high-temperature source
pH: 2.1
The official facility says the source is used as free-flowing spring water, without dilution; it cools naturally as it passes through the baths.Men’s and women’s large baths, open-air baths, a five-stage Awase-yu sequence, sauna and a private bath.

Destination comparison

What this onsen town offers

Popularity

96/100

History

92/100

Spring character

96/100

Town culture

95/100

Seasonal scenery

92/100

Access

68/100

Local history

How the town developed

Kusatsu’s history reaches back to early Japanese tradition. The local tourism association records that Minamoto no Yoritomo visited in 1193. By the Edo period, Kusatsu was a well-known destination for therapeutic bathing, with Yubatake and yumomi becoming central to town life. As transport improved, the spring sources, public baths, inns and streets grew into the walkable hot-spring town visitors see today.

Four seasons

Seasonal conditions and travel rhythm

SpringMarch–May
Daytime range: About 3–16°C by day

Snow can linger into spring. Late spring is more comfortable for longer walks.

SummerJune–August
Daytime range: About 15–27°C by day

The mountain air is cooler, though school holidays and weekends bring more visitors.

AutumnSeptember–November
Daytime range: About 6–20°C by day

Temperatures fall during the autumn-colour season; bring an extra layer for mornings and evenings.

WinterDecember–February
Daytime range: About −4–6°C by day

Snow gives the town its winter look. Allow extra time for walking and transport.

Plan your stay

Kusatsu Onsen: day trip or overnight?

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

Ryokan and stay details

Check the room and bathing arrangements for the plan you book.

Kusatsu Onsen, Gunma

Naraya

A Japanese-style ryokan near Yubatake; only selected room types have a semi-open-air bath.

Planning note Check the room and bath setup for the exact plan you intend to book.

View ryokan details

Related guides

Guides to Kusatsu Onsen

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Official sources

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