Open Friday to Monday (March to November) and Saturday to Sunday (December to February)
¥1,000
Bathing & Water
Outdoor BathYes
Open-air outdoor bath
Indoor BathYes
Enclosed indoor bathing area
Cold BathYes
Cold water plunge bath, typically used after sauna
OnsenYes
Uses natural hot spring water
硫
赤川温泉
Akagawa Onsen
Sampled at drinking fountain
硫
Sulfate
Classification
Calcium Sulfate spring
An acidic cold-mineral spring (21.7 °C) led by calcium and sulfate, with a sulfur character: at the source it turns faintly milky and carries a strong rotten-egg note of H₂S. As a cold-mineral spring below 25 °C it is reheated for bathing. It is rich in metasilicic acid at 96.8 mg/kg, leaving a thin silica film that makes skin feel smoother.
pH
5.30
Acidic
Source temperature
21.7°C
Cold mineral
Tonicity
1.44g/kg
Hypotonic
Free CO₂
642mg/kg
Typical
Free H₂S
29mg/kg
Very high
色
Color
colorless, slightly milky-turbid
味
Taste
moderately carbonated and moderately bitter
香
Odor
strong hydrogen sulfide
Highlights
Sulfur-rich
High silica
Cold mineral
Analyzed Dec 2, 2021·公益社団法人大分県薬剤師会·Cert no. 大薬検第7R-2112000l号
704. Akagawa Onsen, Taketa, Oita ★★
Visited for day-use, 1000 yen. Day-use hours listed as 10:00 to 18:00 (Fri-Mon in March-November, Sat-Sun in December-February). Bath photos from the internet — accurate.
Located 20 minutes by car from Kurokawa Onsen. Very natural atmosphere around with remote countryside vibes. The proper sulfurous onsen smell hits you while still driving up to the building. Despite the inconvenient access — there were quite a few locals. The source itself is cold, which probably explains the number of cold baths.
1. Indoor bath zone. Good air inside. Proper sulfurous onsen smell.
1.1. Bath in the far corner, partially in stone. Milky blue water, around 43°C.
1.2. Bath in the near corner, partially in stone. Milky blue water, cold.
2. Outdoor zone. View of trees, a hill, and a small waterfall. Really wonderful natural atmosphere. Proper sulfurous onsen smell.
2.1. Bath nearest to the exit, in stone. Milky blue water, around 38.5°C.
2.2. Rectangular bath. Milky blue water, cold.
2.3. Bath closest to the waterfall, partially in stone. Milky blue water, cold.
Great place, definitely recommended, but expectations before visiting were even higher — the most scenic bath closest to the waterfall is cold, which significantly limits the experience and doesn't let you fully appreciate the place.
28.12.2025