Onsen With Kids: The Rules Nobody Tells You Before Japan

Children are welcome. Onsen is a family institution in Japan, not an adults-only spa, and nobody will be surprised or annoyed to see your children there.

Everyone is naked, and swimwear is not an option. This is not negotiable and it is not a rule you can quietly ignore. Baths are separated by sex, so you go in with your own children rather than as a family group.

The three rules to check before you go: your child's age against the local limit for entering the opposite sex's bath, whether anyone in your party is still in nappies, and whether anyone has a tattoo. Each has a clean answer, and one solution fixes all three at once.

Here is the scenario. A father takes his eight-year-old daughter to the men's bath because that is how it worked last year, and this year he is turned away. Or a mother brings her nine-year-old son into the women's bath and is asked, politely and unmistakably, to take him out.

Japan's Ministry of Health lowered its national guideline in December 2020, from children of generally 10 and over being barred from the opposite sex's bath to generally 7 and over. The stated reasoning was research into the age at which children themselves reported feeling embarrassed, which landed around six or seven.

But the national figure is a guideline, not a law. The rule that applies to you is set by prefectural and local ordinance, and it varies across the country. As of early 2021, 38 prefectures set an age in their ordinances, ranging from 7 at the lowest to 12 at the highest.

For a ski family, the number that matters most is Hokkaido's. Sapporo lowered its limit to 7 in April 2023, which covers the city most families fly into and pass through on the way to Niseko, Rusutsu and Furano.

Real talk: assume 7 unless you have checked otherwise. If your child is 7 or older and the opposite sex to the parent taking them, plan on the private bath below rather than finding out at the door in a towel.

This one surprises people, because it is the opposite of how a swimming pool works.

Babies and children in nappies are not permitted in the shared bath, and swim nappies do not solve it. A swimming pool is chlorinated and filtered. An onsen is a shared soaking bath that people enter already washed, and the whole system depends on nothing being introduced to the water. A swim nappy is designed for a pool's filtration, not for a bath nobody filters.

Some facilities are stricter still and set a minimum age or require a child to be reliably toilet trained. It varies, and it is worth asking rather than assuming.

This is not a reason to leave a baby out of the trip. It is a reason to book the solution in the next section, which is what Japanese families with babies do too.

If you take one practical thing from this page, take this word.

A kashikiri is a private bath you book for your family alone, usually by the half hour or hour. Many ryokan and hotels have one or several, some at extra cost and some included, and a growing number of rooms come with their own private bath attached.

It resolves every problem on this page at once. Mixed ages, no age limit to worry about. A baby who is not toilet trained, no shared water to protect. A tattoo, nobody else present. A child who is simply anxious about the whole idea, a soft landing before trying the big bath.

Book it when you book the room, not when you arrive. There are only a few slots per evening and ski-season evenings are exactly when everyone wants them. This is the single highest-value ten minutes of planning for a Japanese ski trip with young children.

Tattoos are the other thing that can stop you at the door, and the honest answer is that it depends on the facility to a frustrating degree.

Many onsen refuse entry to guests with visible tattoos. The convention has historical roots in the association between tattoos and organised crime, and while attitudes are shifting, particularly at places used to international visitors, plenty of establishments have not changed the rule.

What actually works:

• Private baths are always fine. Nobody else is present, so no policy applies.
• Ask before you book, not after you arrive. Ski-area hotels used to foreign guests are often relaxed, but you want that established in advance.
• Some facilities permit a covered tattoo, with a patch or sticker, if it is small enough to cover.
• Municipal bathhouses are often more relaxed than resort or ryokan onsen.

None of this is worth being embarrassed about. It is a house rule, not a judgement, and the staff asking are not enjoying the conversation either.

The etiquette that people worry about is the part that turns out to be easy. It is a sequence, and once you have done it once your children will run it themselves.

• Shoes off where the floor changes. There will be an obvious step or a change in material.
• Undress completely in the changing room and leave everything in a basket or locker. No swimwear.
• Take the small towel in, leave the big one behind. The small one is for washing and for modesty while walking.
• Wash thoroughly, sitting down, at the taps before you get in. This is the non-negotiable part. You enter the bath already clean, because everyone shares the water.
• Rinse off all the soap. None of it should travel with you.
• Get in slowly. It is hotter than a bath at home, which is the main thing children need warning about.
• Keep the small towel out of the water. On your head is the traditional answer and children find this delightful.
• No swimming, no splashing, no diving. It is a soak, not a pool. This is the rule children need explained; the nudity is not.

Long hair goes up. Phones and cameras stay in the changing room, always.

Reassurance, since most of the anxiety attaches to the wrong things.

Nobody is looking at you. Onsen is thoroughly ordinary in Japan. Your family being foreign is more notable than your family being undressed, and neither is interesting for long.

Your children will be fine with the nudity. Young children are the least self-conscious people in the building. The parents are the ones who find it strange, and that passes within about four minutes of getting in.

You do not need to speak Japanese. The sequence is visual and everyone around you is performing it. Copying works.

You do not need to buy anything. Towels are usually available to rent or buy for a small amount, and soap is provided at the washing stations.

And the heat is the real hazard, not the etiquette. Onsen water is hot, children overheat faster than adults, and a short soak is the right length. Get out before anyone is uncomfortable rather than after.

If you are still deciding where in Japan to ski, our guides to the best family ski resorts in Japan and Hokkaido for families cover the resorts themselves, and Japan versus Colorado is the honest comparison if you are weighing the flight against a domestic trip.