Open year-round except for occasional maintenance closures; last entry to the main bath is 23:15. The facility has announced it will close for a large renovation and rebrand from September 1, 2026, with reopening planned around January 2027.
¥880
880-930 yen
Bathing & Water
Natural onsen water
Uses natural hot spring water
Outdoor BathYes
Open-air outdoor bath
Indoor BathYes
Enclosed indoor bathing area
SaunaYes
Sauna room of any kind
Cold BathYes
Cold water plunge bath, typically used after sauna
Bathing Arrangements
Private BathYes
A private bath you can reserve for yourself or your group
Mixed BathingNo
Shared bathing area for all genders
Policies & Services
DiningYes
A restaurant or dining room open to visitors, not only meals for overnight guests
WashingYes
Shower, wash stations, soap and shampoo provided
TowelsYes
Towels to rent or borrow at the desk
Stated for the private family-bath rooms; not separately confirmed for the main bath area.
salt's cation — pairs with chloride to make the water salty.
Bicarbonate HCO₃⁻
"soda" — softens skin, leaves it smooth.
Known good for
Smooth skindry, rough skin
Recoveryfatigue, stress
Sayamago Onsen is an alkaline simple thermal spring at pH 8.8, drawn from a 34.4 °C well. The water shows a faint yellow tint, a touch of salt on the lips, and a light hydrogen sulfide note at the source. Mineralization is light (0.419 g/kg), led by sodium and bicarbonate, and the alkalinity gives the water a smooth, slippery feel — it sits squarely in the Japanese 'beauty-water' family.
Sampled at wellhead·Analyzed May 18, 2021·日本水処理工業株式会社
Niji no yu is a large day-bathing complex with a wide range of baths: separate indoor baths for men and women, several sauna styles including one done as ganbanyoku (岩盤浴), and a cold plunge cooled with bincho-tan (備長炭) charcoal. The open-air bath looks out at a waterfall. Reviewers also mention an egg-shaped tsubo-yu (壺湯) tub and a carbonated bath among the lineup. Downstairs, eight reservable private family baths each face the same waterfall and use real onsen water, and there's a restaurant serving housemade soba and seasonal dishes. Some visitors compare the building's white walls and tiled roof to an old castle town.
320. Niji no yu, Osaka ★
A modern super sento with onsen water, about an hour from Osaka Station, for 880-930. Opening hours are listed as 10:00 to 24:00. They stamp the Kansai 41 Super Sento 24/25 stamp rally. There is a diner, massage chairs, massage, and a hyperbaric oxygen chamber. There are private baths, but the staff said it is better to book them two weeks in advance. The main feature of the place is the view of the rocky cliff from the public and private baths, as well as some of the windows in the complex.
1. Outdoor area. A view of the rocky cliff with waterfalls, with trees growing on top. I was there in the evening, and the cliff was lit up. But in the evening, with the lighting, the shape of the cliff, and the trendy atmosphere of the place, the scene felt somewhat artificial. The view itself is also rather narrow, with a roof above, a building on the right, and a fence on the left. In the evening on a holiday there were a lot of people, which also did not add to the atmosphere.
1.1. A two-part bath with a view of the rocky cliff and waterfall. The water is clear, temperature 40. One half of the bath is regular, the other half is a bubble bath. The view from the bath is broken up by two fences, so the bath does not feel infinite.
1.2. Five individual baths for one person, clear water with bubbles, temperature 40.
1.3. Five individual baths for one person, clear water, temperature 38.
2. Inside:
2.1. Bath with clear water, temperature 44.
2.2. Bath with clear water, temperature 40.
2.3. A set of jet baths.
2.4. Electric bath.
2.5. Sauna.
2.6. Cold bath.
Based on the photos on Google Maps, the expectations were much higher, but overall it is an original and distinctive place. Because of its individuality, it is worth considering for a visit in Kansai.
02.01.2025