Onsen OniOnsen Oni

Yunoko Umi to Yuyake

湯の児温泉 海と夕やけゆのこおんせん うみとゆうやけ

Other
Yunoko Onsen
Kyushu & Okinawa·Kumamoto
0966-62-6262umitoyuyake.com

Day Use

Yes

Bathing & Water

OnsenYes

Uses natural hot spring water

Water treatment

from Article 18 disclosure
  • Added water
    Yes
  • Reheated
    No
  • Recirculated
    No
  • Disinfected
    No
  • Bath additives
    No

源泉No.1 及び 源泉No.2 の混合泉

Spring No.1 and No.2 (blended)

Operated by · 湯の児 海と夕やけ

Mixed source

Sampled at mixing tank
曹
Bicarbonate
+ Chloride
Classification

Sodium Bicarbonate-Chloride spring

A blended source drawing from wells No.1 and No.2, a sodium-led bicarbonate water with a chloride sub-type — the classic sodium bicarbonate (jūsō-sen) style finished with a salty edge. Both wells emerge in the low-50s °C and are diluted only when the season pushes them too hot, so the bath stays weakly alkaline and soft on the skin, sitting squarely in Japan's beauty-water family. Metasilicic acid at 62 mg/kg leaves a thin silica film that smooths the skin, while a faint hydrogen sulfide note trails a mildly salty taste.

Source temperature
50.8°C
Hot
Tonicity
2.07g/kg
Hypotonic
Flow rate
157L/min
Typical
Free CO₂
42mg/kg
Low
Radon
1.70Bq/kg
Low
Color
colorless and clear
Taste
slightly salty
Odor
faint hydrogen sulfide
Highlights
  • High silica

Analyzed Jan 28, 2022·株式会社 三計テクノス

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SM
Sergey M
1 year ago

381. Yunoko Umi to Yuyake, Minamata, Kumamoto Visited for higaeri for 500 yen. Higaeri listed as 14:00 to 18:00. They issue Toreco cards for this onsen. Photos from the internet roughly match — I was there in daylight but everything looks very similar. Indoor bath with clear water, temperature around 40. Breathing is good. Before the stairs from the first floor indoor bath to the second floor outdoor bath, there's a box with disposable shorts (but no large sizes), listed as mandatory since if you stand up fully in the outdoor bath you'll be visible from the park. Though if you slide into the water from the edge directly, everything will be fine. Small outdoor bath with a nice view, clear water, temperature around 43. The hassle with the disposable shorts is a bit off-putting, but otherwise it's decent.