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4 min.

What’s an onsen

A Japanese onsen is a thermal spring. Due to the exceptional volcanic activity in Japan, there are thousands of different origins. Each has different minerals and distinct healing properties, but all pleasantly warm and very frequented by the Japanese.

In fact, you actually don’t go to an onsen for its healing properties, but mostly to enjoy a hot bath and relax. Then, very often in traditional ryokans, the onsen might be the only bathroom, as in the beautiful Ganiba Onsen hotel I stayed at in Nyuto Onsen, in northern Honshu.

In Japan, you’ll find onsen everywhere. They can be public onsen, actual true spas, free or for a fee, and more or less beautiful and elegant, natural outdoor onsen (rotenburo) surrounded by peaceful, amazing landscapes (my favorite onsen in Japan!) and private onsen, in a modern hotel or traditional ryokan. But even in the latter case, it could be opened to the public at certain hours of the day (daily access ticket costs from 500 to 1500 yen).

Anyway, you can recognize them by their ideogram 温泉 or ゆ, the one for hot water (yu).

In almost every onsen, you get tubs/pools for mixed-use (konyoku), with men and women simultaneously, only for men or only for women. When it comes to a male onsen, they are called otoko-yu or dansei-no-yu. In contrast, female ones are onna-yu or josei-no-yu, and this is the ideogram 女 you should look for on the door or more often on the curtain (noren, and it took me one hour to understand that this means curtain! I had the poor guy at the front desk of the first onsen I visited in Sapporo gone crazy with it!).

How to behave in a Japanese onsen

First of all: in an onsen you enter naked, as in the Finnish sauna.

Regardless of the type of onsen you enter, there are some rules you absolutely need to follow. Let’s see them, from the moment you enter the locker room:

  • Choose a locker, or more often an overturned basket on the shelf, and undress, putting all your clothes and personal belongings inside it and the slippers they gave you at the entrance right in front of it. You should leave the towel too and keep with you only the tiny white towel you are supposed to use to cover your sex while walking or dab the water when you leave the tub/pool to enter the dressing room. In any case, you’re not supposed to let it into the water, and you’ll see lots of Japanese hold it over their heads. I put it on the side of the tub…
  • Enter the onsen venue and head to the showers. You’ll see that they are at medium height, this is because you will need to sit on the stool to wash (or crouch if there is none), using the provided bowl or spoon to rinse yourself and obviously using the provided soap too (the quality and the choice of soaps varies accordingly to the onsen category)
  • don’t forget to rinse the stool and leave the other items as you found them
  • Enter the water, avoid splashing other people, and, if you can, keep away from the source point, where the water is always too hot to begin within tiny tubs; you can’t avoid a friendly exchange with others… I greet them with konnichiwa and smile, and my Japanese is over! This moment of sharing and extreme intimacy with strangers is called hadaka no tsukyai or naked friendship, and for the Japanese is something essential, because in there they are all equal … Miwa, a sweet lady from Tokyo, was my first “onsen friend,” and she kindly explained all those details to me 🙂
  • after about ten minutes, you’ll be probably leaving the tub (it actually depends on your tolerance to hot water and your blood pressure): dab the water with the small towel not to drip everywhere and walk back to shower or, for softer skin, go directly to the locker room to get dressed
  • if you had a basket, once emptied, turn it again to leave it as you found it 

Between two onsen sessions, you can shower with cold water, wait by the pool, move to another tub or, as I did lately, sit on the snow 🙂 I also used the snow to cool my neck, forehead, and wrists while in hot water!


You are not allowed to enter the onsen with tattoos, and this is because traditionally tattooed people belong to the yakuza, the famous Japanese mafia.

That said, in touristy spas resorts like Noboribetsu Onsen or Nyuto Onsen, tattoos are accepted. They are also generally accepted for foreign women accessing female-only onsen.

However, I recommend you always report it to the staff and ask if it creates any problems: irezumi daijobu wa desu ka? Failing to memorize it I added the sentence to my smartphone notes…


Sentō are as popular as the onsen and involve the same etiquette and the same rules, but they are simply hot public baths and not thermal springs. It’s simple aqueduct heated water.

The ultimate guide to the amazing Japanese onsen

Now I told you what you need to know about the Japanese onsen.

If you plan a trip to Japan and feel that the onsen will be one of the highlights, I recommend this very handy Sento Guide!

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Silvia's Trips

Hi there! My name is Silvia and after 15 years between the Paris Opera and the Palau de les Arts in Valencia I now run a boutique hotel in Cinque Terre, deal with tourism management and blogging, sail, horse-ride, play guitar and write about my solo trips around the world. For more info about me and my travel blog check my full bio.