Onsen, written as 温泉 in kanji, is a Japanese hot spring. Soaking in it is one of the most deeply-rooted tradition and a popular way to pass time and relax in Japan. However, as with anything traditional in Japan, going to an Onsen does come with its own set of etiquette which might not be clear to foreigners like us.
Having been to a few Onsens in Japan, this post passes on all the knowledge I have on experiencing one like a local, and hopefully eases any anxiety you might have about going to onsen! And yes, you do have to be butt-naked 😉 but don’t worry – everyone else will be too.
What is Onsen and why should I go?
Onsen is a dedicated bath house with hot spring water. Yes, the water in Onsen is not just heated tap water (that would be Sento, which I will elaborate on later), it is actually water sourced from natural hot spring with 19 types of minerals. In fact, to qualify as an “Onsen”, the water needs to have 1 of these 19 minerals.
There is an abundant supply of natural hot spring water in Japan due to the amount of seismic activity and volcano on the island, so you’ll see onsens every where you go in Japan. To give you an idea of how abundant it is, there are over 30,000 naturally occuring hot spring throughout Japan.
As I mentioned before, going to onsen is a popular way to pass time in Japan – almost like going to a movie. You go to a dedicated bath house to bathe in hot spring pools. You can go alone for a relaxing me-time or make it a social bonding activity by going with friends and family. I have seen many women go in a group and chat (quietly of course) while dipping in different pools at an onsen.
So why should you try onsen while in Japan? First of all, it is a great way to experience one of the most cherished Japanese culture. Second, bathing in the hot spring water does have medical benefits too! Not only will bathing in onsen help you feel rejuvenated, it is also believed to increase immunity and cure (or provide relief) to certain skin conditions, like eczema or even improving skin texture.
The different types of Onsen pools
Some onsen also have different types of pools – some onsens might have indoor pool, open air pools (rotenburo), pools with natural minerals that is beneficial for your skin and pools with different temperature.
There are 19 minerals that makes up an Onsen water, and each type of Onsen water will contain one of these minerals. They can be identified by color of the water and by smell. The most popular mineral is probably Sulfur, which renders the water a beautiful cloudy milky blue color, and you can definitely smell than rotten egg sulfur smell in the air. There are also Alkaline, Hydrogen, and even Iron water.
Each onsen have their own unique features, but the general etiquette remains the same. Just follow these rules and you should be fine!
1. You must shower before you go in
Just like how swimming pools ask you to wash up before going in, it is good etiquette to wash up before going into an onsen. Furthermore, you have to make sure you are free of any traces of soap before entering the hot spring water, so that you don’t contaminate the water and ruin it for everyone else. There will be showering facilities provided right at the entrance of the onsen with shampoo, body soap and conditioner.
2. You have to go in naked
Yes, butt-naked. No swimsuits, no bikini, no underwear. Except for the small towel they give you in the beginning (if you decide to rent towels from them), no other foreign article is allowed inside the onsen as it may contaminate the water. Also, if you go into the onsen water with your swimsuit, it might damage your swimsuit due to the minerals contained in the water! If you are nervous about being naked, keep in mind everyone else will be naked too. You will stand out more if you attempt to cover up.
3. Can I go in Onsen if I have tattoos?
Tattoos used to be looked down in Japanese culture. As such, there are some rules involving displaying tattoos in public spaces, including in an Onsen. This rule dates back to the days when having tattoos were strongly associated to illegal activities and yakuza (Japanese mafia) members.
I find that this rule has been loosened up in the recent years but it really depends from one onsen to another. I have a small (3-4cm) tattoo of a snake on my back, and most of the time I don’t have issues entering onsen. Recently I did get into a bit of issue at Hoshino onsen in Karuizawa, but even then, I was still able to enter the onsen. I was only asked to cover up the tattoo – they sold me two sheets of skin-colored plaster for 500 yen total. The staff helping me was extremely polite about it! Since then, I make a point to hide my tattoo in order to avoid further issues.
But unfortunately if you have large tattoos, such as a sleeve that cover your arms or a full back tattoo, it might be difficult to enter an onsen. Please ask the front desk first and respect their decision.
4. Caution for Pregnant Women
Pregnant women used to be prohibited from entering onsen, but these days it is totally okay as it has no medical implications for the unborn baby. The concern was more around potentially slipping on the bathroom floor, so make sure you are extra cautious when walking around. I went in onsens 8 month pregnant and I was fine. The floors in all of the onsens I went to was made to be rough (with pebbles) so there was little to no chance of slipping.
5. Do not contaminate the onsen water with your bodily fluids
For obvious reasons, I hope! It is a shared bath after all, so don’t do things you don’t want other people to do. Use the bathroom before entering onsen, and refrain from going to onsen if you have large open wounds. Don’t pee in the onsen. Don’t spit in the onsen. Don’t gargle with the onsen water. I also personally wouldn’t go into an onsen if I am in the middle of my period too, as I don’t want to leak blood and inconvenience others.
6. Do not use your phone or any electronics / smart watches, and definitely NO TAKING PHOTOS!
This is why there are no photos of the inside of an onsen in this blog post. Your phone and electronics must be immediately put away inside the locker at all times, even when you’re at the locker room or vanity area. People will be butt-naked everywhere as soon as you enter the locker room, so try not to have your phone out even if you are just texting or using other apps. It may be a source of anxiety and privacy concern to other onsen visitors. If you need to check the time, there should be wall clock in each onsen rooms so there is really no need to check your phone.
7. Keep your voice down and try to be quiet
Going to an onsen is supposed to be a relaxing activity for some people, so don’t ruin it for them! Chatting among yourselves is totally fine, but make sure to keep your voice down. If people next to you can hear your entire conversation, it’s too loud already! Also, don’t play around with your friends – no splashing or swimming in the water. Do that at a swimming pool instead!
The full guide of how to enjoy an Onsen like a local
Ok, now that we have established the ground rules, here’s what you can expect from going to an onsen in detail:
How much does an Onsen cost?
First and foremost, there is an entrance fee – this can vary from as low as 400 yen for a basic public bath (called “sento”), to 600 yen for a typical onsen, to 1300 yen for a fancy onsen. It might even go up to 1500 yen if it’s a large onsen with multiple pools and additional hot stone facilities.
Sometimes, you buy the ticket from the front desk but sometimes there is a ticket vending machine near the front desk – this is where you should be buying your tickets (and other amenities you want such as towels, comb, etc) instead of approaching the person at the front desk.
What should I bring to Onsen?
You should bring a change of clothes and a set of towels depending on the onsen you go to. Towels are sometimes free or can be rented for about 300 yen extra at the front desk. Either way, you will need to have one small towel and one regular-size towel. If you do not want to rent, you can bring your own towel – just make sure you have one small one, about the size of a face towel, and a regular towel. The small one is to be used inside the onsen, while the regular towel is to be used after showering after you’re done with onsen (as you would after any shower). You can also bring your own toiletries and skincare if you wish – some women do this.
How should I enter an Onsen?
Most onsens are separated by gender. Some onsens are mixed gender or have days where they dedicate the onsen to be mixed gender. In this case, you are expected to rent a bigger towel to cover up your private parts. You can go in the water with these towels.
As soon as you enter the designated onsen area for your gender, take off your shoes (and socks) at the door and place it in the shoe cabinet outside. Sometimes you have to take off your shoes even before you pay the entrance fee – just keep an eye out for shoe cabinet and observe what others are doing.
You can then go inside the facilities, which usually brings you straight to the locker room and a vanity area that you can use later on. Depending on the onsen, you might need some coins to rent the lockers, but sometimes its included in the entrance fare and all you have to do is choose an available one – the ones that are not occupied will have keys hanging outside of it. If it does require coin, it’s usually just 100 yen.
Find an available locker and put your stuff in. Then proceed to strip naked (again, COMPLETELY naked), put your clothes, the big towel and your phone / any other electronics like smart watches inside. Bring only the small towel and keep the locker key with you. Usually the locker key comes with a stretchy band that you can put around your wrist, so you won’t lose the keys while bathing.
You can use the bathroom now if you need to. It’s best to do so while you are still in the locker area before entering the bathing room. There are no toilet once you get inside the bathing area.
Now, you should be inside the bathing area. Before going into one of the pools, don’t forget to wash up! There will be a row of showers right before the pool or right next to it. Unlike western showers, these showers are short – usually about waist height and provided with a small stool, because Japanese people like to sit down while washing up. You can try sitting down while showering too!
After you have washed up thoroughly, and making sure you don’t have any soap remnants on your body, you can finally enter the pool and fully submerge yourself up to your neck. The small towel you brought with you should be folded up and put on top of your head while you are inside the pool. When you are out of the pool, it can be used to cover up yourself if you want to, or kept on top of your head. Do NOT soak your small towel into the pool water!
You can stay in the pool for as long as you can – usually 10-15 minutes – and let your body temperature rise, slowly. But take note not to stay too long! The pools are usually pretty hot – about 40-43C in temperature. Some people are more prone to hot temperature and might get light headed (like yours truly). If you feel that you’re getting too hot, immediately get out and sit outside of the water – usually there are benches around where people can just sit and cool down.
If your Onsen has more than one pool, of course you are free to try each of the pools – but don’t forget to cool down in between! Some Onsens will have a special pool with ice cold water too, which you can use to cool down before going back into the hot water or into the sauna.
Speaking of sauna, most Onsen have a sauna room. In Japan, it’s customary to sit on top of your small towel instead laying your butt naked directly on top of the wooden benches on the sauna area. In some Onsens, there are towels you can pick up at the entrance of the sauna for the purpose of sitting down.
Repeat this process of heating your body and cooling down a few times until you’re happy and relaxed. Typically people stay in an onsen for about 1 hour, depending on how big the onsen is. Some people might even stay an entire half day since some onsens also have additional facilities like hot stone massage or a TV room for you to cool down and take a nap.
What to do after onsen
Once you feel like you’re done, you may take a full shower at the designated shower area. You can wash your hair too – most onsen provide hair dryers in the vanity area. But if you’re going to an onsen with natural minerals, you might not want to wash your body with soap since the minerals are very beneficial for your skin and you want it to stay as long as possible. Just rinse up with water.
When you are done showering, simply put your clothes back on and use whatever amenities available in the vanity area – body lotion, face serums and hair dryer should be provided free to use.
And that’s all! Congratulations on surviving your first Japanese hot spring experience! That wasn’t so bad, right?
I’d also like to add that most onsen has a restaurant within the vicinity. This is a great opportunity to have “washoku” aka traditional Japanese food. The dishes served are soba, udon, tempura, japanese curry (not to be confused with indian or thai curries), katsu (deep fried breaded meat), etc. I personally always time my onsen visits so that I can have a meal after!
How to book a Private Onsen Room (Kashikiri)
Some places might offer a private onsen room called Kashikiri (means “to reserve” in Japanese). Personally I think is totally worth trying at least once especially if you are traveling with an opposite gender partner, so you can go in the onsen together. Otherwise, onsens are usually divided by gender and you’ll be separated. Even if there is a mixed gender onsen, you’ll have to deal with wearing large towels and trying to keep them on, and I find that to be a bit of a hassle.
If you want to do a private onsen room, you can ask the front desk for 貸切温泉 (Kashikiri Onsen – Private Onsen) or 貸切露天風呂 (Kashikiri Rotenburo – Private Open Air Onsen). Do this as soon as you can, preferrably when you are checking in to a hotel, since they have limited time slots and the rooms might be booked up.
Sento (public bath) vs Onsen – what is the difference?
Earlier on this post I briefly mentioned “Sento”. Sento is the term for large public bath houses, and it’s usually a lot cheaper than onsen. This is because the water inside a sento is merely heated tap water so it does not provide any benefit to your skin aside of warming your body up. But sento is still essential to Japanese life, since some people in Japan do not have large bathroom or a bath tub in their house.
I think that’s about all I need to mention about onsen! If you have any questions, please feel free to comment below. I am usually fast in answering and I’ll try to answer to my best knowledge!