First up, a little clarification – an onsen is a natural hot spring whereas a sento is a public bathhouse that uses artificially heated water. Onsen are typically located in upscale resorts and sento in residential areas. Occasionally, onsen are located outdoors and are co-ed, but generally, all types of Japanese bathhouses are indoors and segregated by gender. Whether you find yourself in a sento or an onsen, make sure you read this etiquette guide before you go.
The first thing to do upon entering an onsen (hot spring) or sento (public bath) is to take off your shoes. After that, you’ll head to a designated changing area where everything has to come off. You can bring in a small towel, which can be used to cover up while moving between baths and later to dry off with, but everything else is done in the nude. There are almost always separate bathing areas for men and women; in the rare co-ed baths, people are usually allowed to cover up with a towel or sarong.
Historically in Japan, tattoos are a sign of gang activity. The culture is slowly becoming more relaxed about ink, but many bathing facilities still do not allow people who have them. There are usually signs outside that say whether tattoos are allowed. If your tattoos are small, cover them with a bandage and you should be fine. If your tattoos are big, there are a number of onsens that don’t mind a little ink.
It’s considered disrespectful to other guests to enter an onsen if you’re on your period, especially since sanitary products can’t be worn in onsen baths.
It’s very easy to get dehydrated and overheated while soaking, so it’s best not to drink before or after going to an onsen. Drinking alcohol in onsen baths is strictly prohibited and it is also dangerous as it will dehydrate you even more.
Stepping into the communal baths before rinsing is a huge no. After stripping off all your clothes, head to the shower area – usually a line of taps against a wall adjacent to the baths. Kneel or sit on one of the stools provided and wash fully, as you would in the shower. Only once you are clean can you enter the tub(s). Basic toiletries are usually provided.
Drink lots of water before and after bathing and avoid alcohol for a few hours around your trip. Most sento and onsen have well-stocked vending machines for all your hydration needs, so make sure you have some loose change.
Long hair must be tied up or wrapped up with a small towel. Never submerge your head or let your hair touch the bath water. Basically, the only thing allowed in the tub is a clean body from the neck down.
If you go back and forth between the baths and showers, it is best to rinse in between because this removes any sweat that’s accumulated from a hot soak. However, natural onsen water contains healing minerals, so it is best not to rinse those off when you finally exit. Just make sure you dry off properly before heading back into the changing room.
The bathhouse is a fundamental and unique part of Japanese culture. It’s a great way to experience something new and also feel like you’re getting a spa treatment for what is usually less than 1,000 yen ( USD $10). Simply relax and enjoy!