Confused about Hot Springs in Japan? The Difference Between Onsen, Sento and Super Sento.

When I jump onto Japan travel help forums, I often see people saying they want to go to an "onsen" (or a hot spring) during their travels.

The request sounds simple enough. I mean, the media and all the beautiful travel guides & influencers make it out to be like onsens are littered EVERYWHERE in Japan... is it not?

It's actually really not that simple.

Especially when the travellers want "onsen" recommendations in big cities like Tokyo, Osaka and Kyoto.

First of all, you must understand that there are guidelines to follow in order for a bath or the water to be considered an "onsen". In order to qualify as an onsen, the water MUST naturally have one of these 19 minerals of a certain quantity:

The water must be over 25C and be approved by the Japanese Onsen Law. So as you can see, it is a regulated affair. Does that mean big cities don't have water quality like this? I'm not saying that, but to be fair - it will be quite hard to hit a natural vein in such a high density area that wouldn't be dried up or contaminated in some way over the centuries. So realistically, meeting the request of going to an "onsen" might be a bit of a trick question for most residents trying to help a tourist out.

However, not all is lost.

Just because there may not be natural veins of mineral water, doesn't mean that there aren't baths.

That's where a "sento" comes into play.

What is a Sento?

Bathing culture is huge in Japan, so naturally, demands must be met.

These days, it's common for households to have their own baths and most locals will draw their own baths for daily use. But in big cities like Tokyo, there are still some tiny dwellings that might not have their own bathroom. Share Houses are common also amongst younger people, maybe as their first taste of freedom, where they might have to share one bathroom with many housemates.

Simply put, public bathhouses (or "sento") has become a solution to these modern problems.

And public bathhouses are simply just that. Bathhouses.

They serve the community at large that needs a place to freshen up, where they otherwise wouldn't. Kind of like an airport shower facilities for travelers. They're simple, and they get the job done. They aren't meant to be touristy, but like many things in Japan that exists - if it exists, there is most certainly a fanbase. And there many enthusiasts who find the charm in documenting bathhouses. In fact, some of these bathhouses have historical significance and may be worth a visit for some people.

Definitely check them out if you're interested, or may find yourself in need of one during your stay.

So now, what about "super sento"? Where do they come in?

Super Sento - The Bathing Amusement Park

It's in the name really. It's a sento, but "super(-sized)".

Super sentos are community solutions of a local hangout, a family event or simply just places for friends who want a day of relaxation to go. It's kind of like going to the movie theater to have fun, but instead you're getting naked in a bath with people you know.

And what makes a super sento "super", exactly?

Other than just simple bath facilities, these are full on spa-like giant complexes.

In Osaka, a good example of a popular "super sento" is Spa World:

As you can see, this isn't just the baths (onsen) - they have sauna, swimming and even accommodations. While not in the picture nor advertises, they will often advertise spa treatments like massages, facials and other esthetic treatments geared for women.

The biggest difference with "sento" and "super sento" is that there are a lot of varieties of bathes in a "super sento".

Some iconic selling points may be that they will have a "flavoured bath" that changes every month. A good example of such baths is the famous Yunessun in Hakone and their wine baths. Super Sento will offer one of two of these flavours, along with other varieties like carbonated baths, outdoor baths, hard flat-beds with shallow water, waterfalls, etc etc. You will not find these creative baths in a sento.

Another popular tourist "Super Sento" is Solaniwa Onsen in Osaka:

And Nobeha No Yu (also in Osaka):

These places have a rather large co-ed area where you can wear clothes provided by the establishment to walk around, read some manga, enjoy some food at an extra cost and even have arcades game you can play.

Ok, but why are these Sento still called themselves "onsen"?

You have noticed that some Super Sento also call themselves "onsen". That's probably because there may be one or two baths in the sento that have onsen properties to them. For example, in Solaniwa, there is a bath that they claim have minerals amount that fit the list to be considered an onsen.

Whether you and I believe that is another question entirely...

And I think this is why the concept of super sento and onsen are pretty blurred. Very often these supposed onsen in the cities are actually really "super sento", but they have the word "onsen" in the name. So long story short, if the quote-on-quote "onsen" you are going to has all the frills and conveniences of a recreational complex - it's probably a SUPER SENTO.

Not that there's anything wrong with a super sento.

They can be super fun, and the variety of baths in these super sento can give you a better give you a better money's worth of experiences. Of course though, the idea of a super sento is to trap you in the facility for as long as possible so you would spend extra money, so there is that to consider. But they are great alternative way to experience the bathing culture in Japan, and a good way to test and see if you might be comfortable getting fully naked in a bath or not. After all, if you aren't comfortable, you can just get dressed again and spend your time in areas of the super sento that don't require being naked. They can also be found in almost every city and every tourist hub too.

I hope this clears up the confusion a little bit.

Let us know in the comments or in our social media accounts if you have any questions!