Guide · Onsen
Onsen vs sento vs private bath: which one to choose
A Tokyo sento costs up to $4 (¥600), an onsen day bath $1 to $16 (¥200 to ¥2,500), a private bath from $15 (¥2,400) a slot. Rules and fit compared.
Choose a sento for the cheapest bath in a city, an onsen for mineral water in a hot-spring town and a private bath for privacy. Tokyo caps the adult sento price at $4 (¥600) from 1 Aug 2026. Onsen day baths in our town comparison run from $1 to $16 (¥200 to ¥2,500). Named private baths start at $15 (¥2,400) per slot.
What separates an onsen, a sento and a private bath?
An onsen is a hot spring, a sento is a public bathhouse and a private bath is a bath you reserve for your own group. The Ministry of the Environment defines a hot spring as water that is 25 °C or warmer at the source, or water that contains listed substances at set amounts. The test is the water at the source, not the building.
Private baths are offered at onsen facilities such as Beppu Hyotan and Hakone Yuryo, so the categories overlap. The table shows where they differ.
| Point | Onsen | Sento | Private bath |
|---|---|---|---|
| Price | $1 to $16 (¥200 to ¥2,500) at the day baths we compared | Tokyo adult cap $4 (¥600) | $15 to $39 (¥2,400 to ¥6,000) per slot at named baths |
| Price set by | The operator | Tokyo government sets a ceiling | The venue |
| Who shares | Separate by gender; mixed baths are the exception | Separate; Tokyo bars boys and girls over 7 from bathing together | Your own group only |
| Tattoos | Set bath by bath | Association page is silent | Varies by venue |
| Best for | Mineral water and scenery | Cheap, local, urban baths | Families, couples, anyone uneasy about sharing |
How much does each one cost?
A sento is the cheapest, onsen day baths vary the most and private baths cost the most per slot. Dollar figures use about ¥155 to US$1 and are rounded; you pay in yen, so check the rate.
Sento. Tokyo caps the adult (12 and over) price at $4 (¥600) from 1 Aug 2026, per the Tokyo Metropolitan Government. Children aged 6 to 11 pay up to $1 (¥200) and children under 6 up to $1 (¥100). The Tokyo sento association’s English page still shows the older $4 (¥550); that figure is outdated. The $4 (¥600) is a ceiling, not a fixed price.
Onsen. The operator sets the price. Across the towns we compared, a day bath runs from $1 (¥200) at Yufuin’s Yunotsubo, on an undated city page, to $16 (¥2,500) at Dai-ichi Takimotokan in Noboribetsu, the latter from 1 Aug 2026. Nozawa’s 13 village baths are free, with a donation box at each. Zao’s three communal baths charge adults $1 (¥200).
Passes cut the cost per bath. Kinosaki’s public baths share one $10 (¥1,500) day pass, and Dogo’s three-bathhouse ticket is $9 (¥1,440) for two days.
Private bath. Few venues publish a price, so the table lists the published figures.
| Bath | Price |
|---|---|
| Beppu Hyotan | $15 (¥2,400) for 60 minutes, for 3 adults |
| Mugen no Sato | From $16 (¥2,500) for 50 to 60 minutes, per a Beppu city listing |
| Hakone Yuryo | $25 to $38 (¥3,900 to ¥5,900) per room per hour; one room, Hanare Yuya Kaden, $39 (¥6,000) |
Hyotan prices the slot for 3 adults, so three adults split $15 (¥2,400) into $5 (¥800) each. A main-bath ticket there is $7 (¥1,160). One ryokan-booking guide puts private baths at free to about $32 (¥5,000) per slot, with $6 to $19 (¥1,000 to ¥3,000) typical. Its figures conflict between pages, so read them as a range, not a quote.
Watch the word “private”. A hall rented at Kusatsu’s Gozanoyu costs $13 (¥2,000) an hour, per a secondary guide, and it is a rest room, not a bath.
What are the rules in each one?
Sento and onsen both start with a wash before you get in; a private bath follows the venue’s own rules.
- Sento. Wash at the basin before you enter. No swimsuit or underwear in the water. Bring a small towel and keep your locker key with you. Towels, soap and razors are usually sold on site, and some sento give soap away. Rental prices are not listed.
- Onsen. Wash at the taps, keep the towel out of the tub (Nozawa’s village guide) and skip the swimsuit unless a sign asks for one. Zao’s communal baths ban soap. The Japan Spa Association advises against bathing after alcohol. The full sequence is in Onsen etiquette.
- Private bath. The venue sets the rules. Book at check-in or in advance, and expect access to be limited to overnight guests at some inns, per a ryokan-booking guide. Private onsen (kashikiri) covers the booking steps.
Mixed bathing is the exception. Kusatsu’s Sai-no-kawara Rotenburo allows swimwear or a towel at its Friday-evening mixed bathing, per Kusatsu Onsen’s page. Sento are separated by gender: in Tokyo, boys and girls over 7 may not bathe together, and the age varies by prefecture.
Which one suits you?
Sento for budget, onsen for water, private bath for privacy.
- Sento if you want the cheapest bath, a local one in a city, and do not need spring minerals.
- Onsen if you want mineral water, scenery and a town to move between baths.
- Private bath if you travel with family or a partner, or feel uneasy about sharing a bath. It costs more, and the policy varies by facility.
What about tattoos?
The rule depends on the facility in all three. The sento association’s page is silent on tattoos. One onsen directory (secondary) calls ordinary sento the most welcoming type, without a count, and says super sento and spa complexes mostly prohibit tattoos, with some allowing them if covered.
The same directory calls a private bath always an option. It is not a guarantee: the Hakone tourism page for Hakone Yuryo says “No tattoos allowed” for its main and private baths. Bath-by-bath wording is in Tattoos and onsen.
Before you book Ask whether tattoos are accepted in the private bath itself, not only in the shared baths. Yuryo’s page bars them in both.
To verify The $4 (¥600) cap is Tokyo’s. Check sento prices in other prefectures and the tattoo rules of a named sento with the venue.
Where next?
Best onsen in Japan compared sets the towns side by side. Onsen etiquette covers the rules inside the bath, Private onsen (kashikiri) covers booking, and the Onsen hub covers the rest.
Questions
No. An onsen is a hot spring: the Ministry of the Environment defines it as water that is 25 °C or warmer at the source, or water with listed substances at set amounts. A sento is a public bathhouse, and in Tokyo its adult price is capped at $4 (¥600) from 1 Aug 2026.
Up to $4 (¥600) for adults aged 12 and over from 1 Aug 2026, per the Tokyo Metropolitan Government. Children aged 6 to 11 pay up to $1 (¥200) and children under 6 up to $1 (¥100). The Tokyo sento association's English page still shows the older $4 (¥550), which is outdated.
Not in a sento: the association's page says no swimsuit or underwear. Onsen are usually the same unless a sign says otherwise, according to an onsen directory (secondary). Kusatsu's Sai-no-kawara Rotenburo allows swimwear or a towel at its Friday-evening mixed bathing.
Not always. One onsen directory (secondary) calls a private bath always an option, but the Hakone tourism page for Hakone Yuryo says 'No tattoos allowed' for its main and private baths. Ask the venue when you book.