Kusatsu Onsen Guide: Yubatake, Yumomi and Where to Bathe in Gunma

What shapes a visit to Kusatsu Onsen

Kusatsu Onsen is a town built around one problem: its water comes out of the ground too hot to bathe in. Everything you see in the centre, from the steaming timber channels of the Yubatake to the halls where women churn water with paddles, is there to cool it down.

Kusatsu Onsen in Gunma Prefecture produces 32,000 litres of hot spring water per minute, the highest output of any single onsen source in Japan. Kusatsu Onsen's Yubatake (hot water field) produces water naturally at 51-94°C, and the timber troughs visible in the town centre cool it to bathable temperatures before distribution to ryokan and public baths.

The Japan Onsen official cultural tourism site is a good place to read up on how source water differs between regions, and our own guide to onsen types covers the vocabulary.

If you are comparing Kusatsu against options closer to the capital, my list of onsen near Tokyo sets them side by side.

Hands-Free Private Sightseeing Shuttle from Karuizawa to Kusatsu: what the itinerary covers

This private vehicle transfer starts in Karuizawa and ends in Kusatsu, with an English-speaking guide and luggage storage in the vehicle. Depending on the available time and your preferences, stops can include Harunire Terrace, Onioshidashi Park, Shiraito Falls and Asama Farm.

Use it when you want a flexible, guided route into Kusatsu instead of travelling by bus or train.

Hands-Free Private Sightseeing Shuttle from Karuizawa to Kusatsu

★★★★★ 5.0 (1 review) on Viator · 1 hour 20 minutes to 7 hours

From $100.00

Suited to: Travelers who want a private transfer to Kusatsu with flexible sightseeing stops

Not for: Travelers who prefer to make the Karuizawa to Kusatsu journey by public transport

A private vehicle journey from Karuizawa to Kusatsu with an English-speaking guide, luggage storage and flexible sightseeing stops along the route.

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External booking on Viator · pricing and cancellations handled by Viator

Planning onsen travel in Kusatsu Onsen

The yumomi ceremony is the moment that makes onsen travel in Kusatsu Onsen worth the journey, because it shows you the town's central problem being solved by hand. Kusatsu's yumomi performance, the traditional water-cooling ceremony using large wooden paddles, is a 400-year-old practice originally developed because the source water was too hot to bathe in directly.

I nearly missed it. In February 2024, I made a lazy call. The yumomi performance was listed in every guidebook, so I assumed it would be touristy and skipped it on my first day. On the second day I wandered in ten minutes late. Six women in traditional dress were singing a work song in the local dialect while they churned scalding water with metre-long wooden paddles. The room was a working hot spring hall, not a theatre, and the steam was so thick that my glasses fogged instantly.

Fifteen minutes later the water was cool enough to touch. That was when it clicked for me: the four hundred year old technique was not a performance at all, but something still plainly necessary.

My advice from that trip is to see it early in your stay, ideally on your first evening, and to arrive a quarter of an hour early so you get a seat near the front where the steam hits hardest.

Hot Spring Town Walking Tour in Shima Onsen: who this tour suits

Shima Onsen is another Gunma hot spring town, and this guided walk takes you through its streets with someone who can explain what you're looking at.

Skip this one if your only nights in Gunma are in Kusatsu and you would rather spend every free hour in its baths. It works better as an addition for travellers who have given the prefecture several days.

Hot Spring Town Walking Tour in Shima Onsen

★★★★★ 5.0 (9 reviews) on Viator · 3 hours

From $28.57 · Price checked: Sep 2026

Best for: Guests staying in Gunma's onsen towns

Not for: Visitors expecting a bathing session; it is a walking tour

Guided walk through the Shima Onsen hot spring town in Gunma.

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What Surprised Me About Kusatsu Onsen

What surprised me most about Kusatsu Onsen was the gap between what the ground produces and what your body can take. Onsen water temperatures range from 38-42.

The mineral content of onsen water varies by region; sulfur, iron, sodium chloride are common. The Japan Onsen cultural tourism site explains regional water types in more detail if you want to compare before you pick a town.

Towns handle their heat very differently, and I only noticed that after seeing the contrast. Walking through Kannawa, I noticed steam rising from grates in the pavement every few dozen paces. A local man was lowering a metal basket of corn and eggs into one of the grates on a rope. When he saw me watching, he grinned and said, "Jigoku-mushi, hell steamed. Twenty minutes." I bought onsen tamago from a shop nearby and ate them on a low wall.

If you feel dizzy or nauseous, get out straight away and cool down. Drink water before and after bathing, since an onsen can dehydrate you quickly.

Planning the visit well

Bathe outdoors early in the morning or late in the afternoon to avoid the peak crowds, and walk the lit-up Yubatake after dark, when the day-trippers have gone and the ryokan guests have the evening to themselves.

Don't try to do Kusatsu as a day trip from Tokyo. Book at least one overnight. Skip Kusatsu altogether if you only have a single free day near the capital, and choose somewhere closer from my near-Tokyo list.

Through the fence around the outdoor bath I could see the bamboo forest catching the early light. That was a weekday morning at a river bath far from Gunma, with mist lifting off the water, a temple bell somewhere in the distance and nobody else making a sound. Since then I plan every onsen town around its emptiest hour, and in Kusatsu that means late evening or first thing in the morning.

Winter is the season I would pick for Kusatsu. Winter rotemburo with snow falling is considered the peak onsen experience. Check the Japan Meteorological Corporation for snow forecasts before you travel, and bring a warm hat for the walk between the indoor and outdoor baths. My winter onsen guide and the seasonal breakdown cover the other months.

A few small habits make the stay easier:

• Carry cash and coins. Coin lockers at onsen entrances need change, and rural baths may not take cards.
• Avoid the earliest ryokan dinner slot if you want a slow bath before kaiseki, the multi-course ryokan dinner.
• If a ryokan's booking system is Japanese-only, email them directly in English.
• Use the rest area after you bathe. Look for milk in glass bottles at the vending machine, which is a post-bath tradition.
• For a souvenir, buy local onsen manju, the steamed buns sold in bath towns.

Before you visit

Before my first onsen visits, I wish I had known that etiquette is how a shared bath stays clean and calm for everyone in it, and that it isn't there for show. Wash at the stations before you get in, bathe naked with no swimwear, keep your towel out of the water, and check the curtain before you walk through it.

I learned that last one the embarrassing way. It happened on my first visit to a rural onsen. The curtain colors were hard to read in the dim light and I picked the wrong one. I felt a jolt of panic the moment I stepped through. The attendant redirected me patiently, as though she did this every day. Since then I double-check: blue for men, red for women, and if I'm unsure, I ask.

According to the JNTO guide to onsen etiquette, the bathing rules exist for hygiene and shared comfort, and the details are worth reading before your first bath. Here is what to check before you book or undress:

• Towels should never touch the bath water; place on head or leave outside. The small tenugui towel is for washing, and bringing your own helps because it isn't always included.
• Pull the shower head out of the bucket and sit on the stool to wash, so you don't spray your neighbours.
• Keep your head above the water, because some onsen prohibit dunking for hygiene.
• Leave your phone in the locker, since photos inside the bathing area are prohibited.
• Get out after a short soak, cool down, and go back in if you want more.
• Check whether a ryokan's rotemburo is private or shared, and reserve any private bath (kashikiri buro) when you book the room.
• Check whether a smaller onsen closes on one weekday for cleaning before you book a Monday or Tuesday stay.
• At a ryokan, wear the yukata left side over right, and take your shoes off before stepping on tatami.

Some ryokan with private baths still ask guests to cover tattoos in shared dining areas, so confirm the rules for the whole property, not only the bath. Our etiquette guide explains how to ask. The Japan National Tourism Organization covers wider travel planning for the Kanto region.