Hiratanai Hot Spring (Hokkaido) Complete Guide | From Secret Hot Spring “Kuma no Yu” to Hot Spring Inns – Thorough Explanation
Located in the Kumaishi district of Yako Town on the western side of the Oshima Peninsula in Hokkaido. In this area facing the Sea of Japan, there is a lesser-known hot spring destination called “Hiratanai Onsen (平田内温泉)”. Spreading along the Hiratanai River, the hot spring area is known not only for hot spring hotels and day-use bathing facilities, but also for the secret hot spring wild bath “Kuma no Yu”.
This article introduces the charm of this hot spring area without reservation, from the history and water quality of Hiratanai Onsen, facility information, ways to enjoy wild baths, access methods, and nearby tourist spots.
What is Hiratanai Hot Spring? History and Overview
Hiratanai Onsen is a hot spring destination located in Hiratanai-cho, Kumaishi, Nikkai-gun, Yako Town, Hokkaido. Before the municipal merger in 2005, it belonged to Kumaishi Town, so it is also called “Kumaishi Onsen”. Located about 90 km northwest of Hakodate City, facing the Sea of Japan side, hot spring facilities are concentrated on a highland about 1 km inland from the coast along the Hiratanai River.
Discovery and Development of the Hot Spring
The history of Hiratanai Onsen is old and has long been familiar to local people. This area, blessed with the scenic beauty of a gorge along the Hiratanai River and rich natural environment, is particularly known for offering spectacular scenery during the autumn foliage season.
Development of the hot spring area progressed relatively recently, but the wild bath “Kuma no Yu” in the upper reaches has long been known as a secret hot spring among local people and hot spring enthusiasts. Currently, with hot spring hotels and day-use bathing facilities established, it has become a hot spring destination that is easier for tourists to visit.
Water Quality and Efficacy of Hiratanai Hot Spring
Characteristics of Water Quality
The water quality of Hiratanai Onsen is sodium chloride spring (former water quality name: weak salt spring). A hot spring containing salt content reflecting its proximity to the sea, after bathing, salt adheres to the skin and is characterized by high heat retention effects.
Main Water Quality Data:
- Water Quality: Sodium-chloride spring
- Source water temperature: Varies by facility (approximately 50-60°C)
- pH value: Weakly alkaline to neutral
- Color: Colorless and transparent
Expected Efficacy
Sodium-chloride springs are expected to have the following effects:
General Indications:
- Muscle pain, joint pain
- Neuralgia
- Cold sensitivity
- Fatigue recovery
- Health promotion
Water Quality-Specific Indications:
- Cuts, burns
- Chronic skin diseases
- Weak children
- Chronic gynecological disorders
Chloride springs are also called “hot springs of heat”, and a major characteristic is their high heat retention effect after bathing, so you don’t get cold easily after bathing. In Hokkaido’s cold climate in particular, it is valued as a hot spring that warms the body from its core.
Hot Spring Facility Information
Hiratanai Onsen has hot spring hotels where you can stay and day-use bathing facilities.
Yako Yuraku-tei Kumaishi Hiratanai-so Hot Spring Hotel
The main facility of Hiratanai Onsen hot spring area. Day-use bathing is accepted as well as overnight stays.
Facility Features:
- Located on a highland overlooking the Hiratanai River with good views
- Equipped with large bath and open-air bath
- Local abalone dishes utilizing hot spring heat are a specialty
- Rich dishes using local seafood
Lodging Information:
- Guest room types: Mainly Japanese-style rooms
- Meals: Seafood cuisine using local ingredients
- Check-in/Check-out: Standard times
Awabi no Yu (Day-use Bathing Facility)
A day-use bathing facility built adjacent to the hot spring hotel.
Basic Information:
- Operating Hours: Confirmation needed (may vary by season)
- Closed Days: Basically open year-round (maintenance closures available)
- Bathing Fee: Approximately 500 yen for adults (as of 2025)
- Facilities: Indoor bath, rest area
Access:
- Address: 329 Hiratanai-cho, Kumaishi, Yako Town, Nikkai-gun, Hokkaido
- Parking: Available (free)
Farmed Abalone Using Hot Spring Heat
One major characteristic of Hiratanai Onsen is the farming of abalone using hot spring heat. By utilizing the heat of the hot spring, it is possible to grow abalone faster than normal, providing fresh and thick abalone.
In the meals at the hot spring hotel, dishes using this farmed abalone are a specialty and can be enjoyed in various cooking methods such as sashimi, butter grilled, and steamed abalone. Using regional resources in both hot springs and food, it is also attracting attention as a sustainable initiative.
The Charm and Bathing Guide of Secret Hot Spring “Kuma no Yu”
What cannot be omitted when discussing Hiratanai Onsen is the existence of the wild bath “Kuma no Yu”.
What is Kuma no Yu?
Kuma no Yu is a wild open-air bath in the mountains in the upper reaches of the Hiratanai River. The natural bathing pool carved out of rocks is in an excellent location with the Hiratanai River flowing right next to the hot spring.
Characteristics of Kuma no Yu:
- Mixed-gender wild bath (swimwear recommended)
- Natural bathing pool carved out of rocks
- Can bathe while listening to the murmuring of the Hiratanai River
- Excellent sense of openness in an open-air bath
- Free to use
Precautions When Bathing
When visiting Kuma no Yu, a wild bath, the following points require attention:
Important Precautions:
- Possibility of Temporary Closure: There may be times when bathing is not possible due to weather, river flooding, maintenance, etc. It is recommended to confirm in advance with Yako Town or local facilities.
- Difficulty of Access: It is necessary to walk mountain trails, and there are places where the ground is unstable. Visit with appropriate shoes and clothing.
- No Changing Room/Facilities: As a wild bath, there are no facilities such as changing rooms or lockers. Management of valuables is at your own responsibility.
- Regarding Mixed Bathing: While basically mixed-gender, wearing a swimsuit or towel is recommended. Bathe while following etiquette.
- Trash Disposal: For environmental protection, please take all trash with you.
- Winter Use: Access becomes difficult during the snow season. Use is basically recommended from spring through autumn.
How to Get to Kuma no Yu
To reach Kuma no Yu, you head upstream from the hot spring hotel along the forest road beside the Hiratanai River. It is a distance of approximately 20-30 minutes on foot, but since there are unpaved sections along the way, it is recommended to wear trekking shoes or other non-slip footwear.
As you proceed along the river road, an open-air bath surrounded by rocky areas comes into view. The area around the bathing pool is slippery, so pay careful attention to your footing.
The Appeal of Kuma no Yu
The greatest appeal of Kuma no Yu is undoubtedly the bathing experience in nature. The roaring sound of the Hiratanai River, negative ions falling from the forest, and bathing while sensing nature’s seasonal expressions with your whole body—this is truly the luxury of time unique to a secret hot spring.
The bathing pool is made by carving into rocks and is kept relatively clean for a wild bath. With a large amount of source water being input, fresh hot water is constantly being supplied, so the water quality is excellent. There is a slight slippery feeling, making it a skin-friendly water quality.
It is also popular among campers and motorcycle touring riders, and word-of-mouth has spread it as a spot where you can enjoy a hot spring while fully experiencing Hokkaido’s great nature.
Access Information
Car access is most convenient for getting to Hiratanai Onsen.
Access by Car
From Hakodate Area:
- Head north on National Route 5, take National Route 277 at Yako Town
- Head toward the Sea of Japan side, toward Kumaishi District
- Travel time: Approximately 2 hours
From Sapporo Area:
- Use the Dō-ō Expressway, exit at Yako IC
- Head toward Kumaishi on National Route 277
- Travel time: Approximately 3 hours 30 minutes
From Esashi Area:
- Head north on National Route 229
- Travel time: Approximately 1 hour
Access by Public Transportation
Access by public transportation is limited.
Nearest Station:
- JR Hakodate Main Line “Yako Station”
- Approximately 65 minutes by bus or taxi from Yako Station
Shuttle Bus:
- Hakodate Bus operates a route from Yako Station toward the Kumaishi area, but since there are few buses, advance confirmation of the timetable is necessary.
Taxi Use:
- If using a taxi from Yako Station, it will take over an hour one way and the fare will be high, so advance confirmation and reservation are recommended.
Parking Information
The hot spring hotel and Awabi no Yu have free parking lots. If heading to Kuma no Yu, you can also use this parking lot.
Nearby Tourist Attractions
There are plenty of spots where you can enjoy nature and activity facilities around Hiratanai Onsen.
Hiratanai Gorge
A gorge spreading along the Hiratanai River where you can particularly enjoy spectacular scenery during the autumn foliage season. A walking path is developed along the gorge, where you can enjoy a stroll.
Points of Interest:
- Autumn foliage (peak season is mid to late October)
- Clear stream and rocky landscape
- Bird watching
Kumaishi Youth Travel Village
A comprehensive outdoor facility equipped with a campground and athletic facility.
Facility Contents:
- Auto camp sites
- Bungalows
- Athletic play equipment
- Cooking facilities, restrooms complete
Combined with hot springs, it is ideal for family camping.
Kumaishi Ski Area
A local ski area also operates during winter. Though small, courses are developed that can be enjoyed by beginners to intermediate skiers.
Sea of Japan Coastline
The Kumaishi District faces the Sea of Japan, with a beautiful coastline spreading out. It is also known as a sunset viewing spot, and on good weather days, you can see Okushiri Island.
Recommended Points:
- Sunset view
- Sea fishing spot
- Seashore play (summer)
Michi-no-Eki “YOU・YOU・MORI”
A roadside station located about 40 minutes by car from Hiratanai Onsen. You can purchase local specialty products and fresh seafood.
Yako Town Wooden Carved Bear Museum
A museum in the center of Yako Town that exhibits the history and works of wooden carved bears, a traditional craft of Hokkaido. It is about an hour’s drive from Hiratanai Onsen.
Ways to Enjoy Hiratanai Onsen – Model Courses
Day Trip Plan
10:00 Arrive at Hiratanai Onsen, park your car
10:30 Trek to Kuma no Yu (20-30 minutes one way)
11:00 Enjoy bathing in the wild bath Kuma no Yu
12:00 Return to hot spring hotel
12:30 Lunch at hot spring hotel (savor farmed abalone dishes)
14:00 Bathe again at Awabi no Yu
15:00 Stroll through Hiratanai Gorge
16:00 Depart
1 Night 2 Days Plan
Day 1
15:00 Check in to hot spring hotel
15:30 Stroll through Hiratanai Gorge
17:00 Bathe in the hotel’s hot spring
18:00 Dinner (local seafood and farmed abalone dishes)
20:00 Enjoy the evening hot spring
Day 2
6:00 Morning bath
7:30 Breakfast
9:00 Check out
9:30 Trek to Kuma no Yu
10:00 Bathe in Kuma no Yu
11:30 Nearby sightseeing (campgrounds, coastline, etc.)
13:00 Depart
Camping & Hot Spring Plan
A combination of camping at Kumaishi Youth Travel Village while bathing at Hiratanai Onsen is also recommended. Since the campground is only a few minutes’ drive from the hot spring, you can enjoy both outdoor activities and hot springs.
Charm by Season
Spring (April-June)
- The season when new greenery becomes beautiful with snowmelt
- Kuma no Yu also becomes easier to access after snowmelt
- Mountain vegetable picking season (you might get to interact with locals)
Summer (July-September)
- The most comfortable season
- Perfect for camping and outdoor activities
- Can also enjoy seashore play and fishing
- Bathing in Kuma no Yu is most comfortable
Autumn (October-November)
- The foliage in Hiratanai Gorge is spectacular
- The combination of hot springs and foliage viewing is superb
- Autumn flavors (mushrooms, salmon, etc.) can be enjoyed
Winter (December-March)
- Bathing in a snowy landscape is exceptional
- Winter sports at Kumaishi Ski Area
- Access to Kuma no Yu is difficult (basically closed)
- Recommended to spend time leisurely at the hot spring hotel
What to Bring and Prepare When Visiting Hiratanai Onsen
When Visiting Kuma no Yu
- Trekking shoes or non-slip footwear
- Swimsuit or towel (due to mixed bathing)
- Complete change of clothes
- Vinyl bags (to put wet items)
- Towels (multiple are convenient)
- Drinking water
- Insect repellent spray (summer)
- Flashlight (if visiting early morning or evening)
General Items to Bring
- Bathing set (shampoo, soap, etc.)
- Bath towel
- Change of clothes
- Camera (there are many scenic spots)
- Cash (card payment may not be available)
Summary: Enjoy Hokkaido’s Nature and Hot Springs at Hiratanai Onsen
Hiratanai Onsen is a precious hot spring destination where you can experience two different ways of enjoying hot springs: comfortable stays at a hot spring hotel and the secret hot spring experience of wild bath “Kuma no Yu”. It also has unique attractions such as the beautiful gorge along the Hiratanai River, a rich natural environment, and farmed abalone utilizing hot spring heat.
Though it is somewhat distant from Hakodate and Sapporo, this distance allows you to experience the atmosphere of a simple, non-touristy hot spring destination. By combining it with nearby activities such as the Sea of Japan coastline, campgrounds, and ski areas, you can enjoy a more fulfilling Hokkaido trip.
The autumn foliage season is particularly spectacular, when the beautiful scenery of Hiratanai Gorge and hot springs are perfectly combined. Also, during the summer camping season, it becomes an ideal spot where you can simultaneously enjoy outdoor activities and hot springs.
Since the wild bath “Kuma no Yu” may not be available for bathing depending on weather and season, it is recommended to confirm the latest information before visiting. Please safely enjoy the hot spring experience in Hokkaido’s great nature while taking precautions.
Hiratanai Onsen is an attractive destination not only for hot spring enthusiasts, but also for people who love nature and outdoor enthusiasts. You will surely be able to spend special time refreshing both mind and body in a quiet environment away from daily life.
