By Declan BarryOnsen - natural hot-spring baths - are central to Japanese travel and one of the things tourists most worry about. The etiquette is simpler than the internet suggests. What looks intimidating on paper becomes routine after your first visit: wash, soak, relax. The rules exist to keep the water clean and the atmosphere respectful, not to catch you out.
Most public onsen charge around ¥500-¥1,500 for entry (ryokan guests typically bathe for free). You'll spend 30-60 minutes inside, though some guests make an afternoon of it, rotating between indoor baths, outdoor rotenburo, and cool-down lounges. The reward is genuine: muscle-deep warmth, mineral-rich water, and a particular kind of stillness that follows a proper soak.
Before you arrive
Most onsen ban large tattoos. If you have any, search ahead for "tattoo-friendly onsen" - they exist and they're growing in number, especially in Hakone, Beppu, and Kusatsu. Some places allow small tattoos covered with a waterproof patch, sold at convenience stores for around ¥300-¥500 per sheet. The definition of "small" varies; a single kanji character or a wrist tattoo might pass, but a half-sleeve won't. If you're uncertain, phone ahead or check the facility's website - many now list their tattoo policy explicitly.
Ryokan (traditional inns) tend to be more flexible than commercial sento (public bathhouses), particularly in tourist-heavy regions where staff expect international guests. Rural onsen in Tohoku or Kyushu may enforce stricter rules. The concern isn't aesthetic - it's historical association with organised crime. Younger Japanese bathers are often more relaxed about it than the rulebook suggests, but management sets the policy.
Book your accommodation with the onsen in mind if it's a priority. Ryokan with private family baths (kashikiri-buro) let you reserve a small bath for 30-45 minutes, typically free or for an additional ¥1,000-¥2,000. This solves the tattoo issue and suits anyone uncomfortable with communal nudity. Some high-end ryokan include private rotenburo on your balcony - check when booking.
At the entrance
Pay at the front desk or vending machine. Ticket machines display options in Japanese, though many now include English buttons: "adult" (大人), "child" (子供), sometimes "senior" or "with sauna". Fees average ¥600-¥800 for a standard sento in Tokyo, ¥800-¥1,200 for a commercial onsen resort like Oedo Onsen Monogatari. Ryokan onsen are included in your stay.
Take your shoes off immediately after entering and store them in the getabako (shoe locker), a grid of small cubbies near the door. You'll receive a key, usually attached to a wristband or a numbered tag. This same key opens your clothes locker inside. Some older sento use a single plastic basket for shoes and clothes - bring the basket with you into the changing room.
The entrance splits into two: men (男, blue curtain) and women (女, red or pink curtain). These kanji are worth memorising. Occasionally you'll see 殿 (tono) for men and 姫 (hime) for women at traditional ryokan - lord and princess. Don't guess. If in doubt, wait and follow someone else, or ask staff ("Dochira desu ka?" - which side?).
In the changing room
Strip completely. Onsen is naked bathing - swimwear isn't allowed. This rule is non-negotiable and applies equally to Japanese guests and foreigners, children and adults. The water is shared and treated as a communal resource; fabric introduces soap residue, lint, and contaminants. It feels exposed for about ninety seconds, then becomes entirely normal. Everyone else is undressed, no one is looking, and the focus shifts quickly to the water.
Put your clothes in a locker (or basket) and bring only the small towel (tenugui) into the bath area. The tenugui is typically provided at the entrance, sometimes for an extra ¥100-¥200 rental, or included in your ryokan stay. It's a thin, rectangular cotton cloth about 35 cm × 90 cm - too small to wrap around your body, which is the point. Its job is to wash with and to cover your front as you walk between changing room and bath. Some regulars carry their own; you can buy tenugui at onsen gift shops or any homewares store for around ¥500.
Leave valuables in the locker. Larger onsen provide a separate safe at the front desk for phones, wallets, and watches. Waterproof phone cases are frowned upon - onsen are photography-free zones for obvious privacy reasons. If you're carrying prescription glasses, you can wear them into the bath, though steam will fog them within seconds.
At the wash station
This is the most important step. Sit on a plastic stool at one of the wash stations lining the wall - a low seat with a handheld showerhead, a mirror, and dispensers for soap and shampoo. Soap up, rinse thoroughly. Wash your hair, your body, everywhere. Soap doesn't go in the bath - only clean bodies. Take your time. This isn't a quick rinse; it's a proper wash. Five minutes minimum, longer if you've been travelling all day.
The stool and bucket are communal. Rinse the stool before you sit (a quick splash from the showerhead) and again when you're finished, so the next person finds it clean. Don't let shower spray hit anyone else - the stations are close together, and a stray jet of cold water mid-shampoo is unpleasant. Keep your washing contained to your immediate area.
Some onsen provide razors, combs, and face wash in addition to soap and shampoo. Higher-end ryokan stock branded toiletries - Shiseido, Pola, or regional specialities. Budget sento offer basic dispensers. If you have particular skin needs, bring your own products in a small bag and leave it by your wash station; no one will mind.
Rinse every trace of soap. Check behind your ears, between your toes, under arms. The bath water is re-circulated and filtered but not chlorinated like a swimming pool - everyone's cleanliness maintains it. If you're unsure whether you've rinsed enough, you haven't. Do it again.
In the bath
Step in slowly. The water is 40-43 °C, sometimes higher in particularly robust jigoku (hell) baths in Beppu or Kusatsu. It will feel punishing for the first thirty seconds, then your body adjusts. Don't leap. Don't lower yourself all at once. Sit on the edge, dangle your feet, let your skin acclimatise, then slide in up to your chest.
Soak for 5-10 minutes at a time, sit out on the edge to cool, soak again. Experienced bathers cycle through three or four rounds over the course of an hour. Any longer than ten minutes and the heat becomes counterproductive - you'll feel dizzy, dehydrated, or nauseous. If your heart starts racing or you feel lightheaded, get out immediately and sit somewhere cool. This isn't endurance. It's therapy.
Don't swim, don't splash, don't put your head under. The bath is for soaking, quietly, with minimal movement. Chat if you like - onsen aren't libraries - but keep your voice low and don't disrupt the water. The atmosphere is contemplative. Some regulars close their eyes and sit motionless for the full ten minutes. Others people-watch, gaze at the garden (if it's an outdoor rotenburo), or admire the tilework.
Many onsen have multiple baths at different temperatures. Start with the cooler one (around 38-40 °C) to ease your body in, then progress to the hotter tubs. Outdoor baths are typically a degree or two cooler than indoor, which makes them ideal in winter - cold air, scalding water, steam rising into the dark. If there's a sauna (dry or steam), it's used between soaks, not instead of washing. Always rinse before re-entering the bath.
Mineral content varies wildly. Kusatsu's waters are acidic and milky, said to help skin conditions. Hakone's are sulfuric and smell of eggs. Beppu has nine different onsen types, from iron-red to cobalt-blue. Some leave a slick mineral film on your skin; others feel silky or slightly gritty. All are safe - Japan regulates onsen water quality strictly - but if you have open cuts or recent surgical wounds, ask staff first or stick to the lighter mineral baths.
The towel
Your small towel never goes in the water. Fold it on top of your head (the classic look - practical and absurd) or leave it on the side. The head-towel method keeps it out of the way, prevents it getting soaked from steam, and oddly, helps regulate your body temperature by keeping your crown cool. You'll see every regular doing this.
Use the towel to cover your front when you walk between bath and changing room - a loose drape, not a full wrap. Once you're in the water, it stays dry. When you're finished bathing and heading back to the changing room, wring it out and use it for a preliminary dry-off, but you'll still be damp. Most changing rooms provide a proper-sized dry towel (a bath towel or drying sheet) in a basket or on a shelf. If you don't see one, ask at the front desk - "Taoru wa arimasu ka?"
Don't overthink the towel. It's the detail first-timers fixate on, but in practice it's instinctive after the first visit. Fold, head, done. If you drop it in the water by accident, apologise ("Sumimasen"), fish it out, wring it, carry on. It's happened to everyone.
Hair
Long hair must be tied up so it doesn't touch the water. A bun, a clip, a topknot - anything that keeps it clear of the surface. Loose hair in the communal bath is one of the few etiquette breaches that will prompt a polite word from staff or a harder stare from other bathers. If you don't have a hair tie, buy one at the front desk (around ¥100) or ask if they have spares.
Short hair that doesn't reach your shoulders is fine as-is. Shoulder-length is a grey area; tie it if you can. If you've just washed your hair at the station and it's dripping, give it a quick squeeze with your towel before entering the bath - excessive runoff isn't ideal, though a few drips are unavoidable and acceptable.
Beards and body hair are no issue. Shaving isn't expected (though some wash stations have razors available). Japanese men and women of all grooming preferences use onsen without comment. Modesty about body shape, size, age, scars, or hair is unnecessary - onsen culture is matter-of-fact about bodies.
Outside again
Cool down. Drink water. Onsen dehydrate you - the heat drives fluid out faster than you realise. Most facilities have a water cooler or vending machine near the changing room. Drink at least 300-500 ml after bathing, more if you did multiple rounds or used the sauna. Barley tea (mugicha) is a common free option; it's caffeine-free and lightly flavoured.
Many ryokan onsen are followed by tea and a small mochi, or a cup of amazake (sweet fermented rice drink), offered in the lounge - accept it. It's part of the ritual and aids recovery. Some onsen towns have post-bath traditions: a cold milk drink from a glass bottle (the retro standard), soft-serve ice cream at the exit, or fruit-flavoured ramune soda. Oedo Onsen Monogatari in Tokyo's Odaiba serves this role commercially - yukata-clad guests wander a mock Edo street, eating and drinking between soaks.
Don't rush to dress. Sit in the changing room for a few minutes while your body temperature drops. If you pull clothes on immediately, you'll keep sweating for the next twenty minutes. Let your skin dry naturally, or use the provided towel and a small fan if the changing room has one. In summer, this cool-down is essential; in winter, it's equally important to avoid the shock of cold air on overheated skin.
Your skin will feel soft, your muscles loose, and your mood demonstrably improved. The Japanese term is "yu-agari" - the state of being fresh from the bath. Onsen regulars claim better sleep, clearer skin, and relief from joint pain. The science backs some of this (heat therapy, mineral absorption, muscle relaxation), but the subjective effect is beyond dispute. You'll feel it.
Mixed-gender baths
Konyoku (mixed) onsen still exist in some rural areas, particularly in Tohoku (Aomori, Akita) and mountain villages in Nagano or Gunma. Most are gender-separated now - konyoku declined sharply post-war and continues to fade - but a handful remain, often at old-guard ryokan or volcanic hot springs deep in the mountains. They're not common, and they're not advertised to casual tourists.
If you encounter one, the etiquette is identical: wash first, no swimwear, towel out of the water. Mixed bathing is matter-of-fact, not sexualised, though it can feel confronting if you're unprepared. Some women wrap a large towel around themselves in konyoku baths (a compromise tolerated in mixed settings but not in single-gender onsen). If you're uncomfortable, ask if there's a women-only option or a time-split schedule - many konyoku baths alternate hours.
Today, most onsen strictly separate by gender, with separate entrances, changing rooms, and pools. Some ryokan rotate which side gets the better view (outdoor rotenburo vs. indoor) - men in the morning, women in the evening, or vice versa. Confirm with your ryokan if the outdoor bath is accessible to both or alternates by time.
Private baths and family bathing
If communal bathing isn't for you, kashikiri-buro (private reserved baths) are widely available. Ryokan often include one free 30-45 minute slot per stay; others charge ¥1,000-¥3,000 for the reservation. You book a time at check-in, lock the door from the inside, and bathe with your partner, family, or alone. The etiquette is the same (wash first, no swimwear), but the privacy removes the performance anxiety.
Families with young children use communal onsen regularly. Small children (up to about age 7-10, depending on the facility) can accompany a parent into either the men's or women's bath. Older children bathe with their same-gender parent. Nappies aren't allowed in the water - if your child isn't toilet-trained, stick to private baths or skip the onsen. Some ryokan provide shallow kids' pools at a lower temperature.
Timing and crowds
Public sento are busiest between 18:00-21:00 when locals finish work. If you want space, go mid-afternoon (14:00-16:00) or late morning. Ryokan onsen are calmest before breakfast (06:00-07:30) or late at night (22:00 onwards) - both are magical. The pre-dawn soak in an outdoor rotenburo, mist rising off the water, forest or mountains just becoming visible, is a particular kind of peace.
Weekends and Japanese holidays mean crowds. Golden Week, Obon, and New Year see ryokan and public onsen packed. If you're travelling during these periods, expect full changing rooms and rotation waits at popular baths. Weekday visits to regional onsen (Kusatsu, Kinosaki, Kurokawa) are markedly quieter.
What to bring
Minimal. Most onsen provide everything you need: soap, shampoo, towels (sometimes for a small fee), hairdryers in the changing room. Ryokan include yukatas (casual cotton robes) to wear between your room and the bath. You'll see guests wandering hallways in yukata and slippers - this is normal and expected.
Bring a small drawstring bag if you have personal toiletries or contact lens solution. Bring a hair tie if you have long hair and don't trust the facility to stock them. If you're staying at a budget guesthouse without an on-site onsen and visiting a public sento, bring your own tenugui and a bath towel, or buy them at the entrance.
Leave your phone, your camera, your watch. Onsen time is offline.
