Nagato Yumoto Onsen — photo: Bsx · Public domain · Wikimedia Commons
Onsen with children
Your four-year-old gets as far as the edge of the tub, dips a foot in, and pulls it straight back out with a yell. Every head in the bath turns. The water is 42 °C, which is normal for an onsen and far too hot for a small child. Most trouble with children at an onsen comes down to three things: heat, noise and which door they walk through. All three can be planned for.
Which bath a child goes into
Shared baths are split by gender, so the first question is which side your child uses. Small children go in with either parent, and a father taking a little daughter into the men's bath, or a mother taking a little son into the women's, is completely ordinary. What changes with age is when that stops.
There is no single national age. Each prefecture sets its own limit for children in the bath of the opposite sex, and most now draw the line at around six or seven, so roughly from the start of primary school. Some individual baths set it lower. The rule is usually written on a sign at the entrance, and the words to look for are 混浴 (kon'yoku), mixed bathing, with an age next to it, such as 7歳以上, "age 7 and over". If a child is near the limit, ask at the front desk before you split up at the curtains.
The other end matters too. Many baths do not accept babies and toddlers who are not yet toilet-trained, and swim nappies are generally not allowed in shared water. Some inns say so plainly with おむつの取れていないお子様はご遠慮ください, "we ask that children still in nappies do not use the bath". Others are relaxed about it. There is no legal age for a first bath; each place decides.
The family bath is the easy answer
For small children, the calmest option by far is a bath you book for yourselves. It goes by 貸切風呂 (kashikiri-buro), a private bath booked by the slot, or 家族風呂 (kazoku-buro), "family bath", the usual name in western Japan. You lock the door, and the whole family bathes together whatever the children's ages and genders. Nobody minds a bit of splashing, and you can run cold water into the tub if it is too hot, which you cannot do in a shared bath.
Slots are usually 45 to 60 minutes and priced per room, not per person, somewhere around ¥2,000 to ¥5,000, and some inns give staying guests one free slot. At many inns the sign-up sheet is at the front desk and fills within minutes of check-in, so arrive early rather than after dinner. The details, and how to tell whether a private bath uses real spring water, are in baths you can have to yourself.
The step up is a room with its own bath, 露天風呂付き客室 (rotenburo-tsuki kyakushitsu). It costs much more, but with a toddler who wakes at five in the morning, having the bath outside your door is a very different trip.
The heat is the real problem
Shared baths are commonly kept around 41 to 43 °C, and a small child feels that far more than an adult. The water temperature depends a great deal on what comes out of the ground, and here the records are useful. Of the 1,538 onsen towns we track, 1,167 have a recorded source temperature:
- 237 never reach 25 °C at any recorded source, so their water is heated to whatever the inn chooses.
- 200 top out between 34 and 42 °C, around body temperature to a mild bath.
- 554 reach above 42 °C somewhere, and 152 never come out below 60 °C.
The middle group is the one to look at with children. Water that emerges close to body temperature is often run into the tub as it is, and Japanese bathers have a name for it, ぬる湯 (nuru-yu), "lukewarm water", a bath you can sit in for a long time. Nagato Yumoto Onsen in Yamaguchi is recorded at 39 °C. Kirizumi Onsen in Gunma, a single inn in the mountains, is recorded at 38.9 °C and 300 litres a minute. Takarazuka Onsen, a short train ride from Osaka, is recorded at 38.2 °C.
Where the source is much hotter, the inn has to cool it, and the bath will usually be at the hot end of normal. That is not a reason to skip a town, but it is a reason to look for a tub marked as the cooler one. Larger baths often have several, and one of them is usually gentler. Test the water with your hand, not your child's foot.
Keep the soaks short. A few minutes in, a few minutes sitting on the edge or in the washing area, then back in. Give children water before and after, and leave the bath at the first sign of a red face or tiredness. Adults get dizzy in hot water faster than they expect; children get there sooner.
Water that stings, and water that is slippery
Spring water varies more than most visitors expect, and a few types are worth knowing about before you bring a child.
Acidic water is the one to be careful with. Of the 596 towns in our records with a recorded pH, 26 go below pH 3. Kusatsu Onsen in Gunma, one of the most famous towns in Japan, runs from pH 1.0 to 2.2. Tamagawa Onsen in Akita comes out at pH 1.05 and 98 °C. Water like that stings any scratch, scraped knee or patch of eczema, and it hurts if it gets in the eyes. Children love splashing their faces. Kusatsu is still a fine family trip for its town and its public square of steaming water, but keep the soaks brief and rinse everyone off with fresh water afterwards.
At the other end, 134 towns in our records reach pH 9 or above. Strongly alkaline water feels smooth and slippery on the skin, and the smoothness does not stay in the tub: the stone floor and steps around it get slippery too. Keio Takaosan Onsen, at the foot of Mt Takao outside Tokyo, is recorded at pH 9.9. Hold small hands on the way in and out, whatever the water.
Sulfur springs smell strongly of eggs and can turn cloudy white. Some children find this exciting and some refuse to go near it. The smell also stays in hair for a day, and it tarnishes silver, so take off any jewellery first.
If you want the plainest water for a first try, look for a simple spring, 単純温泉 (tanjun onsen). It has little dissolved in it, is usually clear and mild on the skin, and is the most common type in our records, found in 341 towns.
Noise, running and the rules that still apply
Children are welcome at most onsen, but the bath is a quiet place and other guests have come to relax. The usual signs say 走らない (no running) and 泳がない (no swimming). The rules adults follow apply to children too: wash before getting in, keep the small towel out of the water, and keep long hair tied up.
It helps to practise the washing part at your hotel before the first onsen. A child who knows to sit on the stool and rinse off is most of the way there. If a child needs the toilet, get out and go straight away; do not wait. And if things fall apart, it is fine to leave. Nobody expects a three-year-old to manage twenty minutes.
Booking a ryokan with children
At a ryokan, children are usually priced by age band rather than as a flat free extra. The common Japanese terms are 小学生 (primary school age), 幼児 (pre-school), and plans with or without a child's meal and bedding, shown as 食事・布団あり and 食事・布団なし. A child without meals or bedding often shares a parent's futon for a small charge. Price structures vary a lot between inns, so compare the total, not the headline per-person figure. For how that figure works, see what an onsen night actually costs.
Some inns do not take young children at all, especially small, quiet ones aimed at couples. Look for お子様歓迎 (children welcome) or ファミリー (family) plans, and avoid ones marked 大人のみ or 小学生以下不可, adults only or no children of primary age and under.
A tatami room is itself a good thing with small children: no beds to fall off, and a floor you can all sleep on. Dinner at a fixed hour, often 18:00, fits a child's evening better than you might think.
Things not to do
Do not let a small child go straight into a shared tub without testing the water first. Put your own hand in, then theirs.
Do not bring a child in a swim nappy into shared water, and do not assume the rules are the same at every bath. Ask, or book a family bath.
Do not leave children alone in or near the water, even for a minute, and do not let older children wander into the other side's bath because a younger sibling is there.
And do not plan the whole trip around the bath. For a young child, a paper lantern street, a yukata and a foot bath in the town square can be the best part. Most onsen towns have a free foot bath, 足湯 (ashiyu), where the whole family sits with trousers rolled up and nobody has to undress.
First time in any onsen? Start with how an onsen stay actually works. For a short visit without staying the night, see onsen day trips.