Japanese Onsen (Hot Springs): Etiquette, Temperatures, Tattoos, Rotenburo Explained

What is an Onsen?

An onsen is a naturally occurring hot spring. The characters used for onsen are 温泉. 温, read “on” means warm or hot. 泉, read “sen” means hot spring.

Onsen and Ski Resorts

Onsen are typically enjoyed more in the winter months than hot summer months. Therefore, ski resorts tend to have onsen (or do onsen have ski resorts? Haha). In fact, of the 335 ski resorts we have in our database for Japan, 22 of them already have the word onsen in their name. Of course, you don’t have to have the word onsen in the resort name to have an onsen though. Most resorts tend to have one or two and certainly the larger ones. There are over 25,000 onsen in Japan according to Wikipedia.

Onsen Temperatures and Bath Types

An onsen is typically 38°C to 42°C but there are cooler and hotter onsen available. Typically, larger onsen resorts will have various types of baths from cooler to scorching hot. Some onsen places even have ice cold water to jump into get your blood circulating.

Onsen Facilities and Etiquette

Onsen are normally separated into men and women onsen, although there are mixed ones available but increasingly more difficult to find. Some onsen resorts also offer private onsen in which you can reserve a specific date and time for you and your partner to enjoy, privately. No clothes are worn in an onsen, and especially no bathing suit – butt naked! You can bring in a small towel with you. Many onsen resorts will sell small towels at the entrance for a nominal price. Sometimes you can keep them and other times you must return them. Also, everyone must wash before entering the onsen area. Usually, there is a small stool with a bucket, soap, shampoo, shower and tap. Wash well before entering. Also, try not to splash as this is seen as poor etiquette.

Tattoos and Onsen

Tattoos are normally not permitted although more and more onsen that have a growing foreign customer base tend to allow tattoos, more and more. You can buy various temporary covers for your tattoos on amazon. Ask the onsen if tattoos are ok; who knows? Maybe they’ll say ok.

Rotenburo: Outdoor Onsen

One last note, there are broadly two types of onsen, namely, inside and outside. An outside onsen is referred to as a rotenburo, 露天風呂 literally means “open air bath”. These baths are even more enjoyable when it is snowing and a nice cup of sake … which is probably more for the private onsen though. It is not common to see sake served in public onsen in the actual onsen area.

Remember to bring a larger towel or rent one, too!