Find an onsen ryokan

Spring source

Arima gold and silver springs. The selected guest-room gold-spring bath is explicitly linked to the Tenjin source; the silver-spring source and well number are not published

Spring classification

Gold spring: iron-rich sodium chloride spring, strongly saline, neutral and high-temperature. Silver spring: simple weak radioactive spring, low-tonicity, neutral and cold mineral spring

pH

Not published

Flow rate

Not published

Water handling

Gold-spring water uses a combination of flow-through and circulation, without added water or heating. Silver-spring water also combines flow-through and circulation, with water added and heated. Zuisen and Sosen shared baths use gold-spring water. The reserved Jusen private family bath uses gold-spring water and costs ¥4,400; a separate lockable outdoor private bath uses silver-spring water and is listed as complimentary. Both list hours of 6:30 am–10:30 pm. Selected rooms offer gold, silver or both

Analysis date

Not published

Tattoo policyThe official FAQ asks guests with tattoos not to use the shared baths and suggests booking a private bath. It does not clarify whether the paid gold-spring bath, complimentary silver-spring bath or in-room baths have separate rules; confirm the specific arrangement

Spring source

The inn's own spring

Spring classification

Sodium, calcium, bicarbonate, sulfate and chloride spring

pH

6.4 at the source

Flow rate

Not published

Water handling

The inn describes the open-air and semi-open-air baths in its guest rooms as 100% free-flowing spring water. It does not publish full treatment details for the public bath or every room bath

Spring-source temperature

60.5°C

Tattoo policyThe current public pages checked do not confirm a tattoo policy for the public, private or in-room baths. Ask the inn before booking

Spring source

Kurokawa Onsen water; an individual source is not identified in the current material checked

Spring classification

Sodium chloride and bicarbonate spring / sulfate spring, as listed in current facility data

pH

Not published

Flow rate

Not published

Water handling

The inn's current primary pages do not provide complete water-addition, heating, recirculation or disinfection details for each pool. Some special room types have a bath, but not all room baths are confirmed as outdoor or spring-fed

Tattoo policyThe current official pages checked do not confirm a tattoo policy for the public outdoor baths or overnight family baths. Ask before visiting

Spring source

Arima gold- and silver-spring water. The property’s current main pages do not identify each bath’s individual source or well number

Spring classification

Gold spring: iron-rich sodium chloride spring, strongly saline and neutral. Silver spring: simple radioactive spring

pH

Not published

Flow rate

Not published

Water handling

The ninth-floor Unkai bath area has gold- and silver-spring outdoor baths, shared baths and a sauna. Basement Yurari also has gold-spring indoor and outdoor baths and a sauna. Of five private baths, Akane and Hatsune use silver-spring water, Akebono and Asahi use gold-spring water, and Yubae is not a hot-spring bath. Selected Villa Yuraku rooms use gold spring on the second floor or silver spring on the seventh; a north-wing twin is also listed with a gold-spring outdoor bath. The property does not describe all baths as free-flowing; the association’s current listing says none are. Complete treatment details for each bath are not published

Analysis date

Not published

Tattoo policyCurrent property rules generally prohibit tattoos in shared baths. A small, single tattoo fully covered by a 10 cm × 10 cm cover seal may be allowed. Guests who cannot cover a tattoo are directed to private baths; confirm availability and the current seal policy

Spring source

The inn's own spring, pumped from about 300 metres underground

Spring classification

Sodium, calcium, bicarbonate, sulfate and chloride spring

pH

6.4

Flow rate

Not published

Water handling

The inn describes its own spring water as 100% free-flowing. Eleven private baths are available to overnight guests; room-bath availability is limited to three designated annex rooms. Further treatment details are not published for each bath

Spring-source temperature

60.5°C

Tattoo policyThe inn's current public pages checked do not confirm a tattoo policy for the public or private baths. Ask before booking

Spring source

The inn's own spring

Spring classification

Bicarbonate spring, according to Japan Onsen Association facility data

pH

Not published in current official material

Flow rate

Not published

Water handling

The Kurokawa accommodation listing confirms free-flowing water from the inn's own source. It does not publish full operating details for each bath

Tattoo policyThe inn's public pages checked do not state a property-specific tattoo policy. Ask before using either public or private bathing

Spring source

An unnamed onsen source; the individual source has not been identified on the current main official pages

Spring classification

The inn identifies the room bath as a natural onsen and highlights metasilicic acid content, but does not publish a full formal spring classification on its current main pages

pH

Not published

Flow rate

Not published

Water handling

All eight suites have a private onsen bath. The inn does not fully publish the individual source, water addition, heating, recirculation, disinfection or free-flow conditions for each room. The 16.5°C figure is for the cold bath, not the onsen

Spring source

Gekkoen’s own spring, identified as gold-spring water; the individual source and well number are not published

Spring classification

Sodium chloride spring. The property describes it as 100% spring water; this does not establish that every bath is untreated or free-flowing

pH

Not published

Flow rate

Not published

Water handling

Kinpa-no-Yu and Ginha-no-Yu have indoor and outdoor baths and saunas; the outdoor baths use the property’s own gold-spring water. Staying guests may also use baths at sister property Gekkoen Yugetsusanso; its riverside Afuku-no-Yu and Tamahoko-no-Yu are identified as free-flowing. Korokan’s three paid private baths—Hinoki, Cave and Wine—are not hot-spring baths. Ordinary guest-room baths are not hot-spring baths; selected rooms have natural radon spring water. Full bath-by-bath treatment details are not published

Analysis date

Not published

Spring source

The current official pages do not publish a verifiable formal source name

Spring classification

Sodium chloride and bicarbonate spring

Water handling

Natural spring water supplies all four private baths: two outdoor baths, one indoor bath and one ceramic tub. Current official pages do not provide separate operating details for each bath

Tattoo policyAllowed, according to the current individual facility listing from Oita Prefecture

Spring source

The inn's own spring

Spring classification

Simple spring (weakly alkaline, low-tonicity, high-temperature spring)

Flow rate

Not published

Water handling

The inn describes the baths as free-flowing, with water added to adjust the temperature. It does not publish complete heating, recirculation or disinfection details for each bath

Tattoo policyThe current official bath, room, access and lodging pages do not state a tattoo policy. Confirm before booking

Spring source

Yufuin Onsen; no individual source is identified for the hotel on current official or public tourism pages

Spring classification

A complete legal spring classification is not published in the current primary or public tourism sources checked

pH

Not published

Flow rate

Not published

Water handling

The ten special rooms have 24-hour panoramic indoor baths described by the hotel as 100% free-flowing spring water. The public Kodachi-no-Yu is listed as using Yufuin water with added water, heating and free-flowing supply. These are different arrangements. The standard Japanese-style rooms do not have natural-spring indoor baths

Tattoo policyThe current hotel, group, booking and local visitor pages checked do not publish a tattoo policy for this property. Confirm directly before booking

Spring classification

Simple sulfur spring (mildly alkaline, low-tonicity)

pH

Not published for the property

Flow rate

Not published for the property

Water handling

The outdoor bath is 100% free-flowing, and the small bath is free-flowing. The large bath uses a discharge-and-recirculation system. Hagoromo is generally free-flowing from spring water in spring through autumn, but uses recirculating heating on cold days and during winter. These conditions are bath-specific, not a whole-property rule

Spring source

Murasugi Onsen radium spring; the inn does not publish an individual well number on its current main pages

Spring classification

Radioactive spring; the inn also uses the historical term radium onsen

pH

Not published for the property

Flow rate

Not published for the property

Water handling

The outdoor garden bath includes a heated bathing pool at about 40°C and a low-temperature pool the inn identifies as 100% source water at about 25°C. Other baths also use the spring, but the current pages do not itemize water addition, recirculation or disinfection for every pool

Spring source

Murasugi Onsen radium spring; the inn does not publish a separate well number on its current main pages

Spring classification

Radioactive spring; the inn also uses the historical term radium onsen

pH

Not published for the property

Flow rate

Not published for the property

Water handling

The garden outdoor area includes a heated bathing pool at about 40°C and a low-temperature pool that the inn identifies as 100% source water at about 25°C. The indoor bath also uses the spring, but current pages do not itemize water addition, recirculation or disinfection for every pool. Do not extend the 100% source-water description to the entire facility

Spring source

Kurokawa Onsen water; the current pages checked do not identify an individual source

Spring classification

Salt- and sulfur-bearing spring / simple spring, as stated by the inn

pH

Not published

Flow rate

Not published

Water handling

The inn explicitly describes its spring water as free-flowing. Other treatment details are not fully published for every pool

Tattoo policyThe inn's current public pages checked do not state a property-specific policy. Ask before visiting; rules vary among Kurokawa facilities

Spring source

Arima gold and silver springs. The property’s current main pages do not identify every bath’s individual source

Spring classification

The property confirms both gold- and silver-spring water. The Japan Spa Association lists an iron spring; no current table maps each source to every bath

pH

Not published

Flow rate

Not published

Water handling

The seventh-floor shared baths Hana-gasumi and Hana-goyomi switch between men and women morning and evening. Hana-goyomi has one outdoor gold-spring bath and two indoor baths using gold- and silver-spring water. The private-view bath Hanagokoro uses gold-spring water in 45-minute sessions. Selected guest rooms have gold-spring open-air or semi-open-air baths; ordinary in-room baths are not hot-spring baths. A complete bath-by-bath account of water treatment is not published

Analysis date

Not published

Spring source

Saginoyu Onsen

Spring classification

Radioactive sodium-calcium chloride-sulfate spring, according to the inn's current onsen page

pH

Not published

Flow rate

Not published

Water handling

The inn's FAQ says the men's and women's public baths and the two private baths, Shirotsuyu and Iwatsuyu, all use free-flowing natural spring water. The current main page does not itemize water addition, heating, recirculation and disinfection conditions for each bath

Spring source

Kurokawa Onsen water; an individual source is not identified on the current pages checked

Spring classification

Simple spring (low-tonicity, mildly acidic, high-temperature spring)

pH

Not published

Flow rate

Not published

Water handling

The inn confirms natural hot-spring water in its day-use baths and private baths. Current pages do not publish full water-addition, heating, recirculation or disinfection details for each pool

Tattoo policyThe inn's current public pages checked do not state a property-specific policy. Kurokawa's rules vary by facility, so ask before using either the public baths or a private bath

Spring source

The inn's own spring

Spring classification

Sodium chloride and bicarbonate spring

Flow rate

Not published

Water handling

The inn says every room's indoor and outdoor baths are 100% natural spring water, free-flowing with water added. It does not publish full bath-by-bath details for heating, circulation or disinfection

Tattoo policyThe current official bath, FAQ and room pages do not confirm a tattoo policy. A private room bath is not proof of an exception; ask before booking

Spring source

Saginoyu Onsen; the current property pages do not identify an individual well

Spring classification

Natural hot spring; the inn does not publish a complete property-level analysis classification on the current public pages checked

pH

Not published

Flow rate

Not published

Water handling

The inn explicitly says every bath uses 100% natural spring water, with no added water or heating, and is free-flowing

Spring source

Yubatake, Bandaiko and Sainokawara springs, assigned to different baths

Spring classification

All three are acidic spring systems. The hotel's and Kusatsu-Shirane's published classifications differ in detail, so they are not combined into a single analysis-sheet classification

pH

Yubatake: 2.08; Bandaiko: 1.7; Sainokawara: 2.08

Flow rate

Yubatake system: 4,437 L/min; Bandaiko system: 6,200 L/min; Sainokawara system: 1,400 L/min. These are source-system figures, not the hotel's allocation or bath flow

Water handling

The hotel distributes the three spring sources among its baths. It explicitly describes the large bath and rock bath as 100% free-flowing. For baths whose individual treatment conditions are not published, water addition, heating, recirculation and disinfection are left unspecified

Tattoo policyGuests with tattoos are not permitted to use the hotel's hot-spring baths. No cover-sticker exception or alternative private bath was confirmed

Spring source

Arima Kin-sen and Gin-sen; the inn does not identify the individual source used in each bath on its current main pages

Spring classification

Kin-sen: iron-bearing sodium chloride strong saline hot spring. Gin-sen: simple radioactive spring

pH

Not published

Flow rate

Not published

Water handling

Eight private baths are available to overnight guests at no extra charge. The inn explicitly says they are not Gensen Kakenagashi (source-flowing). It does not publish full water-addition, heating, recirculation or disinfection details for each bath. Room baths vary by room type

Tattoo policyThe current homepage, bath page and FAQ do not publish a clear tattoo policy. Confirm before booking a private bath or a room with an onsen bath

Spring source

Unazuki Onsen water drawn from the Kurobe Gorge's Kuro-nagi source

Spring classification

Simple spring (low-tonicity, weakly alkaline, high-temperature spring)

pH

Not published; only the weakly alkaline classification is confirmed

Flow rate

Not published for the hotel; the 3,000 tonnes/day figure for Unazuki as a whole is not the hotel's allocation

Water handling

The Daikokube indoor baths and Tanayu indoor and outdoor baths use circulation and filtration, with water added and heated for temperature control. The Daikokube outdoor bath and private baths are free-flowing with water added; private baths are not available to day visitors. Women day visitors use Tanayu, while men use Daikokube, so their water systems differ

Tattoo policyGuests with tattoos are not permitted to enter or use the baths. The current policy does not list a cover-sticker exception

Spring source

Ogoto Onsen water, supplied to the property

Spring classification

Alkaline simple hot spring (low-tonicity, alkaline)

pH

9.07

Flow rate

Not published

Water handling

The official hot-spring page confirms Ogoto water in the public bath. Several room types are explicitly marked as having open-air baths supplied with hot-spring water. The property lists 57 open-air-bath rooms among 69 rooms, but that count does not mean every room bath has the same water source or treatment

Spring-source temperature

About 25.6°C at the source

Bathing temperature

Not published; the property manages in-room spring-bath temperature around the clock

Analysis date

Not published

Tattoo policyPublic bath: tattoos are not allowed. In-room open-air baths may be used; free cover patches are available

Spring source

The hotel's own spring, drawn from about 1,500 metres below the entrance's Yudaki feature

Spring classification

Sodium bicarbonate and chloride spring

pH

Not published

Flow rate

Not published

Water handling

The two public outdoor baths are explicitly described as free-flowing; the hotel uses a bamboo cooling channel to bring the hot source water to a bathing temperature. The four indoor baths also use spring water, but their individual circulation and disinfection conditions are not fully published. Do not extend the free-flowing description to every bath

Tattoo policyTattoos are normally not allowed in the large bath. The hotel permits bathing if a cover sticker completely hides the tattoo from other guests; confirm the hotel's current sticker requirements

Spring source

Ogoto Onsen water, supplied to the property

Spring classification

Simple hot spring (low-tonicity, alkaline)

pH

Not published

Flow rate

Not published

Water handling

The official page confirms Ogoto water in both sets of public baths and their open-air baths. Four Premium Floor rooms are explicitly marked as having spring-water open-air baths. Supply and treatment details for other room baths and the private bath are not itemised on the main text pages

Spring-source temperature

Not published

Bathing temperature

Not published

Analysis date

Not published

Tattoo policyPublic baths: tattoos are not allowed. Overnight guests may request the private bath at check-in

Spring source

The pre-closure day-use page did not identify a source that can be confirmed for a reopening

Spring classification

Before closure, the inn listed a sodium chloride and bicarbonate spring; confirm the current analysis after reopening

Flow rate

Not published

Water handling

Before closure, day-use guests could book a private cave bath connected to a garden outdoor bath. The bathing layout and operating conditions after reopening have not been confirmed

Spring source

Sakihana Onsen No. 6 well

Spring classification

Sulfur-bearing sodium-calcium chloride-sulfate spring (mildly alkaline, low-tonicity, high-temperature spring)

pH

7.8, according to the inn's current FAQ

Flow rate

Not published for the property

Water handling

The inn describes the upper-floor observation baths as 100% natural hot spring. Its FAQ says the public outdoor bath and private panoramic outdoor bath use free-flowing spring water. The current pages do not itemize water addition, heating, recirculation or disinfection for each indoor pool, so the outdoor-bath conditions are not extended to every bath

Spring source

The individual source for the annex outdoor gold-spring bath is not published. The separate main-building private bath is explicitly linked to the Tenjin source; do not attribute it to the annex bath

Spring classification

Iron-rich sodium chloride spring, strongly saline and high-temperature

pH

Not published

Flow rate

Not published

Water handling

The garden bath faces the Takigawa and uses gold-spring water. Listed hours are 3:00–11:00 pm and 6:00–10:00 am, with a gender change at about 6:00 am. Current booking-platform Q&A identifies the indoor bath as ordinary water. On some weekdays, a hinoki or maki bath may be available for private family use. Staying guests can separately request the main building’s free-flowing Tenjin-source gold-spring bath in advance. The annex outdoor bath is heated and is not listed as free-flowing. Full bath-by-bath treatment details are not published

Analysis date

Not published

Spring source

Natural Isawa Onsen water; the current official pages do not identify the individual source

Spring classification

Alkaline simple spring (low-tonicity, alkaline, high-temperature spring)

pH

Not published

Flow rate

Not published

Water handling

The hotel lists large baths, outdoor baths, Koshu wine baths and saunas. It does not publish water-addition, heating, recirculation and disinfection conditions for each bath, so the baths should not be described as uniformly free-flowing. The wine bath is a themed bath, not a separate natural spring

Tattoo policyGuests with tattoos are not permitted to use the facility

Spring source

Three springs within the facility; individual source names and current analysis values are not published on the main pages

Spring classification

Natural hot spring. The facility markets it as a medicinal-stone radon bath, but does not publish a formal classification for the source itself on its current main pages

pH

Not published

Flow rate

Not published; the facility describes the three springs as abundant

Water handling

The facility says water flowing from the onsen outlets is free-flowing and not recirculated. Hokutolite is placed beneath the outlets, while Hokutolite and Baden-Baden stone are used in the stone-bed and mist-sauna areas. These materials do not establish that the source itself is legally classified as a radioactive spring. Water addition, heating and disinfection conditions are not fully published

Tattoo policyGuests with tattoos are not permitted to enter

Spring source

The current main official pages do not identify an individual source that can be matched safely to each bath

Spring classification

Simple spring

pH

Not published

Flow rate

Not published

Water handling

The inn explicitly describes the public baths as using circulation, added water and heating. The exact disinfection conditions and source-water distribution for each pool are not fully published. Three private baths are available to overnight guests only, not day visitors

Tattoo policyThe inn's English hot-spring rules prohibit guests with tattoos from entering the bathing area. No cover-sticker exception is published. Ask directly whether any separate rule applies to the overnight-only private baths

Spring source

Ogoto Onsen source

Spring classification

Alkaline simple hot spring (low-tonicity, alkaline)

pH

9.0

Flow rate

Not published

Water handling

The official hot-spring page confirms Ogoto source water in the public baths. The property offers several room types with open-air baths, but the room descriptions reviewed do not confirm natural spring water in every room

Spring-source temperature

About 36°C at the Ogoto source, according to the property

Bathing temperature

Not published

Analysis date

Not published

Spring source

Three springs owned by Sansuien; individual source names are not published

Spring classification

Alkaline simple sulfur spring

pH

9.01

Flow rate

Not published

Water handling

The hotel blends three of its own springs of different temperatures. It says no water is added and no heating is used; the baths are 100% spring-water flow-through

Water treatment: dilution, heating, circulation & disinfection

No added water or heating; described as 100% flow-through spring water

Natural spring use

The public indoor and open-air baths use the inn's own spring. Sauna, cold bath, bubble and jet features are also available, but spring use for each feature bath is not specified

Spring source

The inn's own spring; the current public pages do not publish the formal source name

Spring classification

Radioactive spring. The inn commonly calls it a radium spring; a complete current analysis sheet was not available, so no more specific chemical classification or radon concentration is inferred

pH

Not published

Flow rate

Not published

Water handling

The inn says its public baths, guest-room baths and washbasin hot water use 100% spring water, free-flowing without added water or heating and without recirculation. It does not publish a complete disinfection specification for every bath

Tattoo policyNo current tattoo policy was found on the inn's updated website, main booking pages or the Misasa tourism association listing. Ask the inn before paying if this is important

Spring source

Isawa Onsen water

Spring classification

Alkaline simple spring

pH

9.1

Water handling

The facility describes a circulation and heating system with added water. The bubbling pool uses plain water, not onsen water

Tattoo policyTattoos are not permitted, according to the current facility information checked

Spring source

Multiple Noboribetsu sources, including Springs No. 19 and No. 20; the facility has five spring types

Spring classification

Five types: sulfur, sodium chloride, acidic green vitriol, sodium bicarbonate and sodium sulfate springs

pH

Varies by source. Published examples include pH 2.4 for sulfur water, 2.2 for sodium sulfate water, 6.8 for Spring No. 19 and 6.9 for Spring No. 20

Flow rate

Varies by source. Examples include 60 L/min naturally emerging at Spring No. 19 and 75 L/min blended at Spring No. 20

Water handling

The hotel describes its five spring types as free-flowing. The large complex has 35 baths, and some may be unavailable during daytime cleaning. Individual source and treatment conditions vary; a single source temperature, pH or yield should not be used as a facility-wide value

Spring source

Isawa Onsen water

Spring classification

Alkaline simple spring

Water handling

The source emerges naturally at 31.1°C; the bath is labelled at 42°C. The Hanarei guest-room outdoor bath is described as free-flowing, but that claim should not be extended to the public baths

Tattoo policyA tattoo is allowed only if it is no larger than 20 cm and can be fully covered. Ask the inn if you are unsure whether your tattoo meets the rule

Spring source

The inn's own spring, marketed as Bihada-no-Yu

Spring classification

Alkaline simple spring (low-tonicity, alkaline spring)

pH

Not published on the current official pages checked

Flow rate

Not published on the current official pages checked

Water handling

The inn's current onsen page describes the spring as free-flowing and says it is heated. The large baths and outdoor baths use the spring. Water addition, disinfection and any auxiliary circulation are not itemized for each bath on the current pages

Spring source

Isawa Onsen water

Spring classification

Alkaline simple spring

pH

Not published

Flow rate

Not published

Water handling

The inn's current information describes self-sourced water with some added water, heating and recirculation/filtration. Conditions are not presented as completely free-flowing

Tattoo policyTattoos are not allowed unless completely covered with the inn's official paid cover sticker. Confirm sticker availability and fit before visiting

Spring source

Isawa Onsen water

Spring classification

Alkaline simple spring

Water handling

The listed source temperature is 67.3°C and the bath is labelled 42°C. The women's outdoor pool is explicitly described as free-flowing, without heating or recirculation; this does not establish the same conditions for every bath. The outdoor pool may be cold in winter

Tattoo policyTattoos up to 20 cm are allowed if fully covered. Confirm with the hotel if you are unsure whether your tattoo meets the rule

Spring source

The inn's own spring

Spring classification

Alkaline simple spring

pH

9.2

Water handling

The inn describes its own spring water as serving the baths. Detailed current treatment conditions for each bath are not published

Tattoo policyTattoos are not permitted, according to the inn's current policy

Spring source

Nagano Onsen

Spring classification

Sodium-magnesium chloride-bicarbonate spring (hypotonic, neutral, cold spring). The current main onsen page is used as the reference. An older /r/onsen mirror retains the shorter label “sodium-magnesium chloride spring”; this discrepancy is preserved

pH

6.4 on the current main onsen page. An older /r/onsen mirror lists 6.5; the current main page takes precedence

Flow rate

Not published

Water handling

Natural Nagano Onsen is used in the public indoor and outdoor baths. The inn publishes annual water-quality testing, sodium hypochlorite disinfection, three daily disinfectant-concentration checks, annual high-concentration chlorine cleaning of pipes, and tub cleaning three times a week. Current main first-party pages do not fully disclose water addition, heating or recirculation for each bath, so these are not inferred. The four guest-room baths use natural spring water but are not described as open-air or free-flowing

Analysis date

Not published

Tattoo policyTattoo policy is not published or confirmed. As of 2026-09-07, the inn's current main onsen, FAQ, day-use, room, home and access pages did not confirm whether tattoos are allowed, or specify size, cover-ups or exceptions for the public bath and guest-room baths. A private natural-spring bath in a room does not automatically mean tattoos are permitted; check with the inn before visiting

Spring source

Shirotama-no-Yu, the inn's own spring

Spring classification

Sulfur-bearing sodium chloride-sulfate spring (low-tonicity, mildly alkaline, high-temperature spring)

Flow rate

234 L/min

Water handling

The inn drilled its own spring in 1996 and lists indoor baths, a rock-lined outdoor bath and a reclining bath. Day-use plans combine a meal, bathing and a private room. The regular bathing hours for overnight guests should not be treated as fixed day-use hours

Spring source

Sujiyu Onsen water

Spring classification

Sodium chloride spring

pH

Not published

Flow rate

Not published

Water handling

The inn confirms the use of Sujiyu water, but the current pages checked do not give treatment details for each private bath. The published 76.9°C is the source temperature, not the bath temperature

Spring-source temperature

76.9°C

Tattoo policyAllowed on the current Oita Prefecture tourism listing; follow any day-of instructions from the inn

Spring source

Iwai Onsen water

Spring classification

Calcium and sodium sulfate spring

pH

Not published

Flow rate

Not published

Water handling

The inn says its spring water is kept free-flowing. The women's hinoki bath is specifically described as using 100% spring water without added water or heating; the men's hinoki bath has spring water emerging from the floor. Those descriptions are not generalized to every bath

Tattoo policyThe current official pages checked do not publish a tattoo policy. Ask the inn before visiting

Spring source

Hita Onsen water; the current pages checked do not identify a separate source for the hotel

Spring classification

Simple alkaline spring (weakly alkaline, low-acid spring)

pH

Not published

Flow rate

Not published

Water handling

The hotel and prefectural listing confirm natural hot-spring water in the public bath and in rooms specifically sold with an outdoor hot-spring bath. Current pages do not provide full treatment details for every bath. A '44-degree' reference is not clear enough to use as a source or fixed bath temperature

Tattoo policyThe current hotel and prefectural pages checked do not publish a tattoo policy. Ask about the public bath and rooms with outdoor baths if this matters to your stay

Spring source

The spring used by Hotel Taisetsu; the current official pages do not publish an individual spring name or exact source temperature

Spring classification

Simple sulfur spring

pH

Not published

Flow rate

Not published

Water handling

The hotel says all its baths are free-flowing, with no recirculation. Water is added to bring the high-temperature spring to a usable temperature. The property has three large bath areas and two outdoor baths, with lookout, gorge-side and European-style settings

Tattoo policyGuests with tattoos are not permitted to use the baths

Spring source

A quasi-natural bath using natural mineral stone, Komyo-seki®; there is no natural spring source

Spring classification

Quasi-natural Komyo-seki® bath; not a legally classified natural hot spring

pH

Not applicable / not published as a natural spring value

Flow rate

Not applicable; no natural spring source

Water handling

The indoor bath uses Komyo-seki® mineral stone. It is not supplied by a natural underground hot spring

Water treatment: dilution, heating, circulation & disinfection

Current official text does not fully publish recirculation or disinfection details

Natural spring use

Indoor and open-air baths, cold bath and sauna are available, along with a separately priced family bath. These are not natural hot-spring baths

Tattoo policyTattoos are not permitted; entry is refused

Spring source

Yoshimatsuno-yu

Spring classification

Simple spring (hypotonic, neutral, low-temperature spring), based on a 2018-07-05 analysis. The current official onsen page still publishes this analysis; it is not presented as a new 2026 test

pH

7.1 at the source (25°C); 7.2 in the laboratory (25°C), 2018 analysis

Flow rate

400 L/min (pumping rate), 2018 analysis

Water handling

The hotel identifies the baths supplied with natural spring water and confirms chlorine disinfection. Water addition, heating, recirculation and other supply conditions are not fully published for each bath, so the overall supply is not described as free-flowing

Analysis date

2018-07-05

Tattoo policyTattoo policy is not published or confirmed. A review on 2026-09-07 of the hotel's current home, natural-onsen, private-bath booking, 2026-08-07 private-bath-only notice and access pages found no official rule on tattoos, size, cover-ups or private-bath exceptions. A private-bath product does not automatically mean tattoos are permitted; check directly with the hotel

Spring source

Matsuba Onsen natural radon spring; the individual source name is not published on the current main official text pages

pH

Not published

Flow rate

Not published

Water handling

The public baths and semi-open-air bath use natural radon spring water. Current main official text pages do not fully disclose water addition, heating, recirculation or disinfection for each public bath, so no overall free-flow claim is made. The current booking page states that all six private guest-room open-air baths use 100% natural radon spring water with recirculation and filtration; both details are retained

Analysis date

Not published

Tattoo policyTattoos are not allowed. The operator's current onsen and day-use rules prohibit entry for people with tattoos, including tattoo stickers. The current official pages do not list an exception for covered tattoos

Spring source

Isawa Onsen water used by Kagetsu; the current hotel pages do not identify an individual source

Spring classification

Alkaline simple spring (low-tonicity, mildly alkaline, high-temperature spring)

pH

Not published on the current official pages checked

Flow rate

Not published on the current official pages checked

Water handling

The hotel confirms natural spring water in its large bath and outdoor rock bath. Current official pages do not publish a complete bath-by-bath breakdown of water addition, heating, recirculation or disinfection. A third-party free-flowing description is not treated as a current official specification

Spring source

The current official pages do not identify an individual source that can be matched safely to every bath

Spring classification

Simple alkaline spring

pH

Not published

Flow rate

Not published

Water handling

The hotel confirms natural spring water in its public baths, upper-floor outdoor baths and private Tenryu family bath. The 50-minute private bath has an indoor and outdoor pool. Current pages do not give a full treatment breakdown for each bath. Ordinary room bathrooms are not assumed to use spring water

Tattoo policyThe hotel's current FAQ and bath pages do not state a clear tattoo policy. Ask about public and private bathing before visiting

Spring source

Nagahama Taiko Onsen

Spring classification

Iron spring (the operator's current published description; a more detailed classification is not published)

pH

Not published

Flow rate

Not published

Water handling

The operator's current onsen page confirms that iron-rich spring water from the Nagahama Castle ruins area is used in the public bath and Shigaraki-ware outdoor bath. Private baths can be booked for day use, but the current text does not confirm that they have the same supply conditions as the public bath, so no such assumption is made

Analysis date

Not published

Spring source

Two spring systems: the milky-white spring and the reddish-brown spring

Spring classification

Milky-white spring: sulfur-bearing sodium bicarbonate spring (hydrogen sulfide type; neutral, low-tonicity, high-temperature spring). Reddish-brown spring: sodium bicarbonate spring (neutral, low-tonicity, high-temperature spring)

pH

Milky-white spring: 7.0; reddish-brown spring: 6.7

Flow rate

Not published

Water handling

The hotel describes both spring waters as free-flowing. The Torinokoe and Kawa-no-Sasayaki bath areas offer the milky-white and reddish-brown waters, and both have saunas. The current main pages do not publish water addition, heating, recirculation and disinfection details for every bath in a complete itemized format

Spring source

Kin-sen: Daiichi Shinrei-sen. Gin-sen: radon spring; the current site does not map a complete source number to every bath

Spring classification

Kin-sen: iron-bearing sodium chloride strong saline hot spring. Gin-sen: simple weak radioactive spring

pH

Not published

Flow rate

Not published

Water handling

The public Hoshi-no-Yu has one Kin-sen indoor bath and one Gin-sen outdoor bath for each side. The inn labels them 100% natural hot spring, but does not publish full treatment details for each pool. Five designated suites have natural baths; ordinary room bathrooms do not

Tattoo policyThe current official FAQ, bath page and main lodging rules do not publish a tattoo policy. Confirm before paying if you plan to use the public bath or a room with an onsen bath

Spring source

The hotel's own Tamano-yu spring

Spring classification

Sodium chloride-sulfate spring; clear, faintly salty and odorless

pH

8.4

Flow rate

Not published

Water handling

The hotel uses its own spring in a free-flowing system. The 99.4°C source is cooled by adding water. Some of the 12 baths use recirculating filtration, and some use chlorine-based agents for sanitation; the hotel does not say that every bath has identical treatment

Tattoo policyNot permitted. The hotel says the restriction applies regardless of tattoo size or occupation and includes stickers and other coverings

Spring source

Centrally managed Gero Onsen water, supplied from the Gero Onsen cooperative's tank through a dedicated pipe

Spring classification

Alkaline simple spring

pH

9.1

Flow rate

1,250 L/min for the centrally supplied Gero Onsen system, not Fugaku's individual spring output

Water handling

The public baths use a partial discharge-and-recirculation system, with some heating to maintain temperature and chlorine-based sanitation. The inn describes the private bath as free-flowing, but does not publish a complete bath-by-bath treatment table for it. The hinoki bath in the panoramic suite is explicitly not a natural hot spring

Tattoo policyGuests with tattoos may not use the public baths or outdoor baths, regardless of size or type; stickers are included in the restriction. The current official text does not state whether tattooed guests may use the private bath, so ask before booking it

Spring source

Tomonoura Onsen; the current main pages do not publish the property's individual well name

Spring classification

Simple weak radioactive cold mineral spring (radium spring)

pH

Not published on the current main property pages

Flow rate

Not published on the current main property pages

Water handling

Natural hot-spring water is used in the third-floor large bath and outdoor bath, which are the standard day-use areas. The rooftop observation bath and rooftop private bath are for overnight guests. Current text pages do not fully specify water addition, heating, recirculation, disinfection or free-flow conditions for each bath

Spring source

Isawa Onsen water

Water handling

The inn describes its hot-spring baths as free-flowing. Current material does not give a full technical breakdown for every bath

Spring source

The inn's naturally emerging Kan-juku-no-Yu system: Juku-no-Yu and Kan-no-Yu

Spring classification

Alkaline simple spring

pH

Not published in the current material checked; an older historical figure is not used as a current value

Flow rate

1,415 L/min total, according to the inn's current homepage

Water handling

The springs emerge naturally on the property. The inn states that the baths are 100% free-flowing, with no recirculation, heating, added water or chlorine disinfection. Spring water is also used at the washing stations and showers

Spring source

Naturally emerging Shirabu Onsen spring water; the official page does not identify an exclusive Fudokaku source

Spring classification

Sulfur-bearing calcium sulfate spring

pH

Not published

Flow rate

About 1,300–1,500 L/min, listed by the inn for the Shirabu source; not presented as Fudokaku's exclusive output

Water handling

The inn describes natural emergence and says fresh water continuously enters the view-facing Olympic bath. The current text pages do not publish a complete bath-by-bath statement on water addition, heating, recirculation or disinfection, so the entire facility is not described as untreated free-flowing water

Spring classification

Iron-rich sodium chloride spring (gold spring), strongly saline and high-temperature. Guest-room open-air baths are not hot-spring baths

pH

Not published as a current value. The older Gokuraku certificate listed pH 6.4

Flow rate

Not published as a current value. The older Gokuraku certificate listed 51 L/min

Water handling

Hinoki-no-Yu and Higurashi-no-Yu switch between men and women morning and evening and offer gold-spring open-air bathing. Yuzuriha-no-Yu has an indoor plain-water bath and a gold-spring bath; Natsume-no-Yu has a plain-water bath and a semi-open-air gold-spring bath. Each private bath is ¥3,300 for 45 minutes, with sessions listed from 4:00–11:00 pm and 5:00–9:00 am. Guest-room open-air baths are not hot-spring baths. Full bath-by-bath details on dilution, heating, circulation and disinfection are not published

Analysis date

Not published

Tattoo policyThe official FAQ says tattoos and body art are not allowed in shared baths unless covered with the property’s cover seals, sold at the front desk from ¥330 each. Ask about larger or multiple tattoos and private-bath terms

Spring source

A blend of five springs: Sakura-no-Yu, Naka-no-Yu, Kawa-no-Yu, Ai-no-Yu and Okunosawa Fukiage spring

Spring classification

Simple-spring family; individual springs have separate analyses, but the current main page does not publish one classification for the blended water

pH

Not published for the blend. Kawa-no-Yu alone was pH 7.5 in a 2015 analysis

Flow rate

Not published for the blend. Kawa-no-Yu alone had a natural yield of 96.0 L/min in a 2015 analysis

Water handling

The inn blends five of its own springs to adjust the temperature. Kawa-no-Yu is an outdoor bath made by damming a natural hot-spring stream and is described as 100% free-flowing spring water. The inn also describes its indoor bath as free-flowing. Day visitors cannot use the private Oku-no-Yu bath

Spring source

A blend of Hijiori Association Springs No. 2, 3 and 4

Spring classification

Sodium chloride-bicarbonate spring (low-tonicity, neutral, high-temperature spring)

pH

6.9 in the inn's published analysis dated July 2, 2010

Flow rate

Not published

Water handling

The inn describes the baths as free-flowing. Because the source is hot, water may be added and the water may also cool naturally. The spring is used in the large bath, private bath and seasonal rock bath

Spring source

Shirabu Onsen water; the inn's current text pages do not identify a dedicated Higashiya well

Spring classification

Calcium sulfate spring; the Shirabu Onsen association also describes the wider area as sulfur-bearing calcium sulfate water

pH

Not published for the inn

Flow rate

Not published for the inn; the association's 1,500 L/min figure is for Shirabu Onsen as a whole

Water handling

The inn explicitly describes the day-use baths as 100% free-flowing. Bath-by-bath water addition, heating, recirculation and disinfection details are not itemized on the current text pages

Spring source

The inn's own spring blended with Hijiori Spring No. 5 for the fourth-floor day-use baths

Spring classification

Sodium chloride-bicarbonate spring

pH

Not published for the blend used in the fourth-floor day-use baths

Flow rate

Not published

Water handling

The inn describes the fourth-floor baths as 100% free-flowing, without added water or heating. Day visitors can use Jizo-no-Yu and Kannon-no-Yu on the fourth floor. A 69.0°C figure on the same official site refers to a different spring and is not assigned to this blend

Spring source

Natural radium spring on the Nanten-en grounds at Amami Onsen

Spring classification

Natural radium spring (simple, mildly radioactive spring; hypotonic, neutral, cold spring)

pH

Not published

Flow rate

Not published

Water handling

The private cypress open-air bath at Seiryu-tei uses naturally emerging spring water on a free-flow basis, as stated by the operator; this applies only to that guest-room bath. The Gokuraku-yu public baths are recirculated and filtered. The operator has not published full details on water addition, heating or disinfection for each public bath

Analysis date

Not published

Tattoo policyTattoos are permitted in the public bath, provided guests follow basic bathing etiquette. The operator's current FAQ does not specify size, cover-sticker or nationality restrictions; this permission is confirmed for the public bath

Spring source

Fushio Onsen, from the inn's own spring

Spring classification

Natural sodium bicarbonate spring; current official pages give pH 8.99. An older Japan Onsen Association listing classifies the water differently, so its figures are not combined with the current official data

pH

8.99

Flow rate

Not published

Water handling

The inn identifies natural spring water in the large bath and garden outdoor bath. Current official pages do not publish treatment details for each pool. The outdoor bath attached to the day-use room and the ¥5,000 private bath are explicitly not onsen

Tattoo policyGuests with tattoos are not permitted to use the large public bath or outdoor bath

Spring source

Hagi Honjin's own spring

Spring classification

Calcium–sodium chloride spring

pH

Current property-specific pH not published

Flow rate

Current property-specific yield not published

Water handling

The hotel describes 14 bathing experiences based on its own spring. Only the spring-water cold bath is specifically identified as continuously flowing; do not assume all baths are flow-through or untreated

Water treatment: dilution, heating, circulation & disinfection

The hotel says the baths are heated, filtered and recirculated, with chlorine-based disinfection. The spring-water cold bath is an exception, described as continuously flowing spring water

Natural spring use

The 14-bath circuit includes indoor and open-air options, sauna and a spring-water cold bath. Treatment differs by bath; see the notes above

Spring source

Hagi Onsen; the specific source name is not published in current official text

Spring classification

The hotel lists two classifications: radioactive calcium–sodium chloride cold mineral spring, and calcium–sodium chloride cold mineral spring. It does not map each one to a particular bath

pH

Not published

Flow rate

Not published

Water handling

The hotel confirms spring water in its two sea-view open-air baths and private semi-open-air bath. It does not publish water-addition, heating, recirculation or disinfection details for each bath. The large rock baths are explicitly not hot springs

Water treatment: dilution, heating, circulation & disinfection

Water handling is not fully detailed bath by bath. The rock baths use natural stone as a design feature, not natural spring water

Natural spring use

Two open-air baths and a bookable private semi-open-air bath use Hagi Onsen. The large rock baths, Uminari no Yu and Ariso no Yu, are not hot-spring baths