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Hirayama

植木温泉 旅館 平山うえきおんせん りょかん ひらやま

Lodging
Kyushu & Okinawa·Kumamoto

Day Use

Yes
MonClosed
Tue10:00–16:00, 18:00–22:00
Wed10:00–16:00, 18:00–22:00
Thu10:00–16:00, 18:00–22:00
Fri10:00–16:00, 18:00–22:00
Sat10:00–16:00, 18:00–22:00
Sun10:00–16:00, 18:00–22:00

except Monday

¥700

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathYes

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

Cold BathYes

Cold water plunge bath, typically used after sauna

Policies & Services

WashingYes

Shower, wash stations, soap and shampoo provided

ParkingYes

On-site or nearby parking available

横井温泉

Yokoi Onsen
Simple
Color
colorless and transparent
Taste
slightly salty
Odor
faint hydrogen sulfide
pH 8.7AlkalineHot source · 49°CTop-decile alkaline
Known good for
  • Aches & jointsstiff shoulders
  • Smooth skindry, rough skin
  • Recoveryfatigue, stress

Yokoi Onsen is an alkaline simple thermal spring at pH 8.66 and a generous 48.7 °C wellhead temperature. Mineralization is light (evaporation residue 691 mg/kg) and sodium-led, with a faint trace of hydrogen sulfide on the nose; the water feels notably slippery on the skin and sits squarely in Japan's beauty-water family.

Sampled at wellhead·Analyzed Jul 29, 2018

Explore the water

Programs

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4.0

1 review

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Sergey M
1 year ago· edited

385. Hirayama, Ueki Onsen, Kumamoto ★★ Stayed overnight for ¥11,000, without meals. Day-use bathing is also available for ¥500, listed from 10:00 to 16:00 and from 18:00 to 22:00, except Mondays. They also stamp the Kyushu 88 Onsen stamp rally booklet. A simple, warm, old-school ryokan, with a very friendly woman at reception. This was the setting for one of the cool stories I wrote about earlier. When I checked into the ryokan in the evening, I asked them to call a taxi early the next morning to take me to another onsen. Then I came downstairs, and the woman ran out from reception and handed me a kind note in Russian saying they would take me there. A little later she came up to me with a pencil and asked me to leave my signature on the wall, where her guests sign. In the morning, before checking out, I of course gave her a matryoshka doll. Her reaction to the word “matryoshka!” was very lively and positive. In the translator, she wrote that she had only seen matryoshka dolls on TV before, and now she was seeing one in person. At the appointed time, a separate man arrived and drove me to the onsen I had wanted to go to, without any extra charge. In the indoor bath, the water was clear, with the right slightly sulfurous onsen smell, and the temperature was 41. It was comfortable to breathe inside. The open-air bath is set in stone, the water is clear, and the temperature is 42. Of course, a place with this kind of warmth is recommended for a visit. 10.01.2025 11.01.2025

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Last updated July 25, 2026