Glossary

Vocabulary

Japanese terms you'll see commonly used in the context of onsen and sento bathing.

Onsen (温泉, おんせん, ♨️): Natural hot springs and the bathing facilities built around them. Entry to an onsen is often more expensive than a sento, but not always. Entry is often ¥700 - ¥1500 per adult, but some public onsen are free. Onsen often have more amenities than sento, e.g. free hair dryers in the changing rooms, while some are very rustic.
Sento (sentō, 銭湯, せんとう): A public bathhouse that uses heated tap water rather than a natural hot spring. Some sento treat the water they use with chlorine, but usually the smell is very mild compared to, say, pools in the United States. Sento are often very affordable, between ¥500 - ¥700 for an adult to enter. Some sento can be very small, quite old, and offer few or limited amenities. (For example, it's common to have to pay extra to use a hair dryer.) On the other hand, there are also "super sento" that are large and offer many amenities, including hangout/chill spaces and dining options.
Yu (湯, ゆ): Yu means hot water or bath, often used in names for baths and bathhouses. Many locations will use yu in their name. For example, Hana no Yu means Bath of Flowers or flower bath. Tattoo no Yu means Tattoo-Friendly Bath. ☺️
Furo (風呂, ふろ): Furo means bath and is typically used to refer to the bathtub & bathing water itself. In Japanese, "bathing" doesn't mean "to get clean" - it means "to enter & sit in the bath" after having already cleaned your body.
Konyoku (混浴, こんよく): Mixed bathing. These are baths where people of different genders may bathe together. While historically common in some locations, most modern facilities have separate bathing areas for men and women, so mixed bathing is somewhat rare these days, unless you reserve a private bath.
Rotenburo (露天風呂, ろてんぶろ): An outdoor or open-air bath, typically located outdoors to allow bathing with a view.
Yokujō (浴場): "Bathhouse" and also "public bath" - this is the common / generic term for a shared bathing facility without being overly specific. It applies to both onsen and sento.
Higaeri (日帰り): This is the word that means "day use" bathing. Use this term to ask if a facility allows non-overnight guests to use their bath during limited daytime hours.
Kazokuburo (家族風呂): Literally meaning "family bath" and sometimes used as the word for "private bath" that can be booked for exclusive use for a limited time by one or multiple people in the same group.
Irezumi (入れ墨 or 入墨 or いれずみ, also 刺青): Japanese words for tattoo. いれずみ (irezumi) is the traditional Japanese term. When used in the context of contemporary tattooing practice or tattoo artistry, this term likely refers to specific Japanese techniques of tattooing by hand without a machine. When used in the onsen/sento context, it is probably referring to tattoos that are actually, or suspected to be, associated with gang membership or criminal activity.
Tattoo (タトゥー): Japanese word for tattoo. タトゥー (tatū) is the contemporary borrowed term from English. Both terms are used interchangeably in Japan to refer to tattoos, but sometimes this term is used specifically to mean "art tattoo" (especially on foreigners), not necessarily ink associated with gang membership or criminal activity. However, such tattoos are often still prohibited at onsen and sento. The Japanese spelling of tattoo is helpful to know, since you might encounter it on signs or in website FAQs.

Facility Tags

A guide to the tags used in the database so you can filter for the bathing experience you want.

Public

This facility is open to the public. Public facilities are run by a private business. They're often no-fee or very inexpensive (i.e. 100 JPY) and payment is on an honor system, usually a collection box at the entrance.

No Fee

This facility is free to use. No payment is required for entry or usage.

Ryokan

This onsen or bath is located inside a ryokan, a traditional Japanese inn. Unless this facility also has the Day Use tag, you must stay overnight at the ryokan to use it.

Hotel

This onsen or bath is located inside a hotel. Unless this facility also has the Day Use tag, you must stay overnight at the hotel to use it.

Day Use

This facility can be used on a day-use basis, without staying overnight. Unless this facility also has a Ryokan or Hotel tag, this facility is not usable at night.

Mountain Hut

This facility is located in a mountain hut or lodge, typically found in alpine or forested areas. These facilities are often seasonal and may be accessible only during specific times of the year. For some mountain huts, the only way to access them is to hike or trek, often for several hours. The notes will have a comment about accessibility.

Private Bath

This facility has private baths available, either as part of an overnight stay booking or available as a separate service. Some day-use facilities also offer private baths. (If so, they'll be tagged as such.) Almost always, private baths can be shared by multiple people in a party, and mixed bathing is allowed.

Sauna

This facility has a sauna. In Japan, saunas are often dry, but not always. Many are Finnish-style saunas, but some are infrared-heated. Facilities with a sauna often also have a Cold Plunge.

Cold Plunge

Cold bath, or 水風呂 / みずぶろ / "water bath." This facility has a bath filled with very cold water.

Indoor Bath

The bathing area is located indoors, typically within a building or structure. This is the most common configuration, but some facilities are outdoor-only!

Outdoor Bath

The bathing area is located outdoors, typically in a natural setting such as a garden or open-air area, although even facilities in the city sometimes have outdoor baths.

Mixed Bathing

This facility allows both men and women to bathe together in the same area. Most facilities are gender-separated, but some do allow mixed bathing, either always, on certain days or during certain times. Policies about body covering during mixed bathing vary by facility. Some facilities require men to cover themselves with a towel or loincloth while bathing. Others prohibit men from covering themselves during mixed bathing. Often, women have the option to cover or not with a special "bathing dress" or towel provided by the facility.

Onsen

This facility is a traditional Japanese hot spring bath, often found in rural areas or smaller towns.

Sento

This facility is a traditional Japanese public bathhouse, often found in urban areas. Sento facilities are typically community-oriented and may have a more casual atmosphere compared to private or high-end establishments. I've never been to a sento that cared about tattoos, so these are overwhelming safe places for tattooed people!

Super Sento

A modernized version of a traditional Japanese public bathhouse, often larger and featuring upgraded amenities and facilities compared to regular sento. Super sento often have some kind of restaurant or food service, large areas for relaxation and socializing, and may offer additional services, such as massage therapy.

Adjustable Temp

The temperature of the bath can be adjusted by the user. This is typically only found at very rustic locations, basic public facilities, or private baths that you must reserve with or without an overnight booking. Look for a water spigot (often with a handle, sometimes with a button) at the edge of the bath and open the spigot to add colder water and cool the bath to the desired temperature.

Cold Spigot

This facility is equipped with a cold water tap. This can be used in place of a cold plunge if you're into that! Fill a bucket with water from the cold spigot and pour it over your body. I recommend taking short breaks from the bath to do this, then getting back into the bath!

Electric Bath

電気風呂, or でんきぶろ, or denkiburo. This facility has a bath with an electrical current running through it that provides an electro-stimulating effect in your body when you enter the bath. Sometimes this effect can be very intense, so be careful! You can tell when a bath is electrified from the signage (look for the 電 kanji on the wall) or, when you look into the bath, you'll see two panels on the walls of the bath, one each on opposite sides. These panels carry the current into the bath water.

Shared Bath

This facility is neither an onsen, a sento, nor super sento, but it does have a bathing area and baths that are not private and used by mutiple people from different groups at once. Facilities with this tag do not use hot spring water to fill the bath. In Japanese, shared or common baths like this are often called "public baths" (公衆浴場, こうしゅうよくじょう, kōshū yokujō) even though such baths are sometimes only available for guests who are staying overnight at a hotel or ryokan.

Alternating Sides

Baths are often gender segregated in Japan, and at most facilities, the women's side and the men's side are fixed, and never change. However, at facilities with this tag, the gender assignment of the bath sides do change on some regular interval. (Usually AM/PM or every other day.) At such facilities, the two sides are often assymetrical and offer different features, so visiting multiple times on the correct schedule will allow you to experience all of their baths!

No Showers

This facility doesn't have showers or an area in which you can properly wash your body before entering the bath. At places like this, you can either arrive having already washed yourself elsewhere, or you can simply rinse your body by pouring water from the bath over yourself using a bucket or ladle (often provided) before entering the bath.

Swimwear Allowed

This is one of those rare facilities that allow swimwear in the baths. (And, at some locations or at some times, requires swimwear for some guests.) Check my notes for the specific details for each location!