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Niji no yu

狭山郷温泉 虹の湯 大阪狭山店さやまさとおんせん にじのゆ おおさかさやまてん

Waterfall-view baths and eight private family rooms

Bathing Complex
Kansai·Osaka

Day Use

Yes
10:00–00:00

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.

Rest AreaYes

Relaxation space for after bathing

ParkingYes

On-site or nearby parking available

Water treatment

Treated and recirculated(partial disclosure)
from Article 18 disclosure
  • Added water
    Yes
  • Reheated
    Yes
  • Recirculated
    Yes
  • Disinfected
    Yes
    塩素系薬剤
  • Bath additives
    Not disclosed

狭山郷温泉

Sayamago Onsen

Operated by · ホテルザフラッグ株式会社

湯
Simple
Color
pale yellow and clear
Taste
slightly salty
Odor
with a hydrogen sulfide note

Sodium Bicarbonate-Chloride spring

pH 8.8AlkalineTop-decile alkaline
Composition fingerprint0.4 g/kg dissolved · Hypotonic
Na⁺92
HCO₃⁻62
Cl⁻22
CO₃²⁻15
◀ CationsAnions ▶
Sodium Na⁺
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

Explore the water

Views

Waterfall

Highlights

Electric Bath
Jet Bath

About

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.

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1 review

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Sergey M
1 year ago· edited

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

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Last updated October 13, 2026