Aso Hinoyama Onsen Dondoko-Yu

火の山温泉どんどこ湯ひのやまおんせんどんどこゆ

Bathing Complex

Minamiaso Onsen

Kyushu & Okinawa·Kumamoto

050-3773-4753 dondokoyu.com

Day Use

Yes

Mon11:00–22:00

Tue11:00–22:00

Wed11:00–22:00

Thu11:00–22:00

Fri11:00–22:00

Sat07:00–22:00

Sun07:00–22:00

11:00-22:00 (Mon-Fri) and 07:00-22:00 (Sat-Sun)

¥900

¥900 on weekdays, ¥1000 on weekends

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathYes

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

SaunaYes

Dry heat sauna room

Cold BathYes

Cold water plunge bath, typically used after sauna

Capabilities

Mixed BathingNo

Shared bathing area for all genders

Site shows separate men's/women's indoor and outdoor bath galleries; no mixed bathing mentioned.

Policies & Services

KidsYes

Welcomes children and families

DiningYes

Restaurant or dining open to visitors (not just hotel meal plans)

WashingYes

Shower, wash stations, soap and shampoo provided

TowelsYes

Towels available to rent or borrow

Rest AreaYes

Relaxation space for after bathing

ParkingYes

On-site or nearby parking available

火の山温泉

Hinoyama Onsen

硫

Sulfate

Magnesium-Calcium-Sodium Sulfate spring

High silica

Composition fingerprint3.3 g/kg dissolved · Hypotonic

Mg²⁺43

Ca²⁺30

Na⁺23

SO₄²⁻77

Cl⁻16

◀ CationsAnions ▶

Magnesium Mg²⁺: mild; a laxative if you drink it.
Sulfate SO₄²⁻: "gypsum / Glauber's salt" — vessels and wound healing.

Known good for

Aches & jointsstiff shoulders
Circulationtired legs
Smooth skindry, rough skin

A magnesium-calcium-sodium sulfate spring (41.8 °C), neutral and moderately mineralized at 3,332 mg/kg — settled, mineral-rich body without a heavy edge. A touch of metasilicic acid layers in a soft, slightly silky feel on the skin.

Analyzed Jul 19, 2002·社団法人熊本県薬剤師会医薬品検査センター

Explore the water

Highlights

Jet Bath

Lukewarm Bath

Programs

About

Dondoko-yu is a big day-use bathhouse on the road through Minami-Aso, with about a dozen separate tubs split across the men's and women's sides. The indoor baths come in three temperatures, hot, medium, and a milder nuruyu (ぬる湯), plus a sauna and a cold plunge, while the outdoor bath is built into a small garden of lava rock and planted trees. The water itself is a cloudy greenish-white, unusual for this part of Aso, and it's kept flowing fresh from the source rather than treated. Inside there's a restaurant, a free rest and reading lounge, a table-tennis corner, and a small shop selling local vegetables and yogurt, the kind of place people settle into for a few hours rather than just pass through.

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1 year ago· edited

433. Aso Hinoyama Onsen Dondoko-Yu, Kumamoto ★★ A super sento with onsen water for ¥660 in Aso. Opening hours are listed as 11:00 to 22:00 (Mon-Fri) and 07:00 to 22:00 (Sat-Sun). They stamp the Kyushu 88 Onsen stamp rally. The bath photos from the internet match. There is a diner, a shop, places to relax, table tennis, and a hyperbaric chamber. 1. Indoor area. Inside, there are two large stones in the center, and the interior is made to feel warm too, with wood used in the washing area. The baths inside are designed in a non-technical way, and are pleasant as well. 1.1. First half of the main bath. The water is cloudy, whitish-green, at 43-44. 1.2. Second half of the main bath. The water is clear, slightly cloudy pale green, at 40-41. 1.3. Oval bubble bath. The water is clear, slightly cloudy pale green, at 38. 1.4. Sauna. 1.5. Cold bath. 2. Outdoor area. The land area is also nicely arranged, with different stones placed there, and moss on them. Around it, there is a view of the trees, and even though there is a fence, it can still be seen pretty well. 2.1. Large outdoor bath. The water is clear, slightly cloudy pale green, at 40-41. 2.2. Small outdoor bath with older men, the water is cloudy, whitish-green. A nice, cozy place. If you visit Aso, it is highly recommended. 16.01.2025

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Last updated July 22, 2026