The first time we took a friend visiting from overseas to a hot spring, she stood frozen at the changing room door for a solid ten seconds. "Wait, actually naked?" Yes, actually naked — and once you know why, and the handful of small rules that go with it, an onsen stops being intimidating and becomes one of the best things you'll do on a trip to Japan. This is what actually happens from the moment you walk in, what's true about tattoos in 2026, and how to pick between an onsen, a sento, and the swimsuit-friendly option if full nudity isn't for you.
Onsen, sento, or super sento: which one are you actually at?
These three words get used loosely by English guides, but they're not interchangeable. By Japanese law, water only counts as an "onsen" if it comes out of the ground at 25°C or higher, or contains at least one of nineteen specified minerals — it has to be real geothermal water. A "sento" is a plain neighborhood bathhouse that heats ordinary tap water; it's not fancier or cheaper by definition, just different water. A "super sento" is a larger bath complex, often with saunas, outdoor pools and sometimes a separate swimsuit-mandatory family zone next to the regular naked-bathing floors. None of this changes how you behave once you're inside — the etiquette below applies to all three.
| Type | Water | Swimsuit? | Typical day-use fee |
|---|---|---|---|
| Onsen (hot spring) | Natural geothermal water | No — nude bathing | ¥300–¥2,000 (~$2–$13) |
| Sento (neighborhood bath) | Heated tap water | No — nude bathing | ¥400–¥500 (~$3) |
| Super sento / onsen theme park | Either, often mixed facility | Nude floors + a separate swimsuit zone at some locations | ¥1,000–¥3,000 (~$6–$19) |
Fee ranges as of October 2026, cross-checked across multiple English-language guides; always confirm the specific facility's price before you go, since it varies a lot by region and luxury level.
The shower comes first, every time
Before you so much as dip a toe in the bath, you wash. Every onsen has a row of low shower stations with a stool, a basin, soap and shampoo. You sit, rinse, lather, rinse again, and only then walk to the bath. This isn't a suggestion — it's the one rule nobody will let slide, because the bathwater is shared and isn't being drained and refilled between guests. If you only remember one thing from this article, remember the shower.
Chopi: "I kept worrying I was taking too long at the shower and holding up the line."
Log: "Nobody's timing you. The thing people actually notice is someone who skips it."
What to do with your towel, your hair, and your head
You'll usually get two towels: a large one left in the changing room, and a small one you carry into the bathing area. The small towel is for modesty on the walk over and for washing — it is not supposed to go into the bathwater. Most people fold it and set it on top of their head, or leave it on the edge of the bath. If you have long hair, tie it up; hair touching the water is treated the same as a towel touching the water. Submerging your whole head isn't done either — an onsen is not a swimming pool, and nobody is doing laps.
Yes, you're expected to be nude — and that's not a loophole
Almost every traditional onsen and sento requires full nudity, with bathing areas separated by sex (often marked with a red curtain for women and blue for men). This isn't a dress code gap tourists are supposed to get around with a swimsuit; it's the actual norm, rooted in a bathing culture that treats shared nudity as unremarkable rather than something to manage. A Japan Tourism Agency guidance notice from 2016 even weighed in on this directly, stating that facilities shouldn't refuse guests for reasons unrelated to hygiene — the agency's position is that nudity itself isn't the problem foreign visitors sometimes assume it is.
Our own first time was years ago at Dōgo Onsen in Matsuyama, one of Japan's oldest bathhouses — Chopi nearly turned back at the door the same way our friend did later. The payoff was a glass of cold mikan (mandarin orange) juice from the machine right outside afterward, which is apparently the correct way to end a soak in that part of Shikoku, and is still the detail either of us mentions first when the topic comes up.
Tattoos: the real 2026 picture, not the old warning
This is the question we get asked most, and the honest answer is "it depends, more than it used to." There's no national law banning tattooed guests — tattoo policy is set facility by facility, which is exactly why the advice online is so inconsistent. Roughly half of onsen facilities now accept tattooed bathers in some form, up from closer to a third just a few years ago. What you'll actually run into:
- Fully tattoo-friendly — increasingly common, especially at facilities used to international guests.
- Conditional — small tattoos (roughly palm-sized or smaller) are allowed, often with a skin-tone cover seal over them. These seals are sold at some facilities and at general stores like Don Quijote.
- Strictly no tattoos — still the rule at some traditional or very local bathhouses, regardless of size.
If you don't want to gamble on walking up and being turned away, book a private kashikiri bath (common at ryokan, rented by the hour for your own group) or check a facility's policy before you go — many now state it on their own website.
Log: "I still cover mine with a seal even at places that technically allow it, just so nobody at the next tub over has to decide how they feel about it."
Chopi: "That's basically just being a good guest."
If nude communal bathing isn't for you
You don't have to skip the experience entirely. Some larger onsen theme parks and super sento complexes run a separate mixed-gender zone where swimsuits are required (rental suits are usually available on site), kept apart from the traditional nude floors. It's a different, more amusement-park atmosphere than a quiet ryokan bath, but it's a real option if you're traveling with kids or would rather not go nude on your first visit. The alternative, if your budget allows it, is simply booking a hotel or ryokan with a private in-room or reservable bath, which sidesteps the question altogether.
What to bring — and what to leave at the desk
Pack light: your wallet, phone and clothes stay in a locker or basket in the changing room, not with you in the bathing area. Phones and cameras are a hard no past the changing room — this is one of the few onsen rules with essentially zero tolerance, for obvious privacy reasons. Food and alcohol aren't brought in either; soaking while intoxicated is treated as a genuine safety issue, not just bad manners, and most guides suggest capping a single soak around 30 minutes so you don't overheat. One thing you won't need: cash for a tip. Service charges at bath facilities work the same way they do everywhere else in Japan — if you want the full picture on why nobody expects a gratuity here, we covered it separately in our guide to tipping in Japan.
FAQ
Do I really have to be completely naked at an onsen?
At a traditional onsen or sento, yes — swimsuits aren't worn in the nude bathing areas, and a small modesty towel is for the walk over, not the bath itself. If that's a dealbreaker, look for a super sento with a swimsuit-mandatory zone, or book a private bath.
Can I go to an onsen in Japan if I have a tattoo?
Often, but not guaranteed — about half of facilities now accept tattooed guests, sometimes with a condition like a cover seal for larger designs, while some traditional spots still refuse outright. Check the specific facility ahead of time, or book a private kashikiri bath to remove the question entirely.
What's the actual difference between an onsen and a sento?
Legally, an onsen uses natural hot-spring water that meets a specific temperature or mineral-content standard; a sento heats ordinary tap water. The bathing etiquette — shower first, no towel or hair in the water, no swimsuit — is the same at both.
Once the shower-first rule and the towel habit are automatic, an onsen stops feeling like a test you might fail and turns into one of the more relaxing hours of a Japan trip. If a ryokan stay with its own bath sounds easier than a public one for your first time, that's a completely normal way to start.
