What Is an Onsen? Japanese Hot Spring Baths Explained

Japan has several types of bathing facilities, and the terminology can be confusing if you’re not familiar with it. Here’s a quick breakdown of each one and what makes them different.

Onsen (温泉)

An onsen is a hot spring bath fed by naturally heated volcanic water.

Japan’s volcanic geography produces thousands of these across the country, each with a different mineral composition. Many claim specific health or healing properties depending on the minerals in the water, though you can use your discretion regarding these benefits.

Onsen come in a wide variety of settings and can be found in both cities and rural areas. The key distinction: if it’s fed by natural volcanic spring water, it’s an onsen.

Sento (銭湯)

A sento is a public bathhouse that uses regular heated and chlorinated water, not natural spring water. These are neighborhood bathhouses found across Japan’s cities and have been part of daily life for centuries.

Sento are generally:

• Smaller and more local than onsen
• Found in residential neighborhoods
• Affordable (usually a few hundred yen)
• A part of everyday Japanese routine, not just a tourist experience

If you want a simple, authentic bathing experience in the middle of a city, a sento is the place to go.

Super Sento

A super sento takes the public bathhouse concept and scales it into an entire complex. Think of it as a bath-themed facility with multiple pools, saunas, steam rooms, restaurants, lounging areas, and sometimes entertainment like manga libraries or karaoke.

Super sento are:

• Large commercial facilities, often found near major cities
• Popular for day trips and group outings
• A mix of regular heated water and sometimes natural spring water (varies by location)
• Reasonably priced, usually between 1,000 and 2,500 yen

If you want the longest, most relaxed bathing experience with the most variety, a super sento is a great choice.

Quick Comparison

Terms To Know

Here are some additional words usually associated with onsen that you may come across:

• Rotenburo (露天風呂): An outdoor bath. Found at some onsen and sento. Usually the highlight of the experience, especially at locations with scenic views.
• Kazokuburo (家族風呂): A private family bath you can rent by the hour. Available at some onsen and super sento. More expensive than standard entry, but with the added benefit of privacy.
• Hitou (秘湯): A hidden or secret hot spring. These are remote, hard-to-reach onsen often considered the most authentic experiences for those willing to make the journey.

All three facility types are worth experiencing during your time in Japan. Which one you choose depends on your budget, your location, and how much time you have.

The Culture Shock Japan app includes a full guide to visiting an onsen, including etiquette, what to bring, and what to expect step by step. Available on iOS.