A simple weakly radioactive spring carrying 236.8 Bq/kg of radon — well into the radon-spring tradition associated with the 'hormesis' lore. Total dissolved solids sit at a light 729 mg/kg, so the water itself reads gentle on the body, weakly alkaline and soft on the skin. At 26.8 °C the source is a cold-class spring and is reheated for bathing.
Source temperature
26.8°C
Low temp.
Tonicity
0.73g/kg
Hypotonic
Flow rate
83.3L/min
Typical
Radon
237Bq/kg
High
色
Color
colorless and transparent
香
Odor
odorless
Highlights
High radon
Analyzed Oct 11, 2019·株式会社ケイ・エス分析センター·Cert no. 大阪府 10
638. Matsuba Onsen Taki-no-yu, Kaizuka, Osaka ★
A ryokan 20 minutes by car or 50 minutes by public transport from Kansai Airport (KIX). Visited for day use at 720 yen. Day use available from 09:00 to 21:00. They stamp the 88 Onsen of Wakayama stamp book. Bath photos from the internet match.
1. Outdoor zone. Close-up view of trees with a road behind them (you can occasionally glimpse cars through the trees, but it's not bothersome and the natural view stays intact). There's a lattice fence that does detract from the view, but not dramatically.
1.1. Small bath with clear water, temperature 42.
1.2. Large bath with clear water, temperature 38. Strong water circulation and a smooth bottom — you have to get used to lying in it so your body relaxes without sliding around.
2. Inside, a room with a high ceiling and wooden beams. Bath with clear water, temperature 41. The drains were running noisily during my visit, but it was still quite cozy. Breathing inside is good.
A solid place worth keeping in mind for day use if you're passing by, or as a ryokan conveniently located near the airport.
03.11.2025