Kojohama Onsen: The Seaside Sanctuary of Abundant Springs and Coastal Delicacies
Kojohama Onsen is a hidden thermal giant located on the rugged Pacific coast between the bustling port of Tomakomai and the famous resort of Noboribetsu. Known to hot spring aficionados as the “Onsen with the No. 1 Water Volume in Hokkaido,” this area is unique because nearly every hotel, guesthouse, and even some private homes are supplied with 100% pure, natural-flowing spring water. Kojohama doesn’t offer the flashy theatricality of its neighbor Noboribetsu; instead, it provides a quiet, authentic retreat where you can soak in “Beauty Waters” while listening to the roar of the Pacific waves. Historically significant for its proximity to ancient Ainu settlements and famous across Japan for its world-class cod roe (tarako), Kojohama is a place where thermal luxury meets the raw bounty of the northern sea.
Key Information
| Address | 〒059-0641 北海道白老郡白老町虎杖浜 / Kojohama, Shiraoi Town, Shiraoi District, Hokkaido |
| Google Maps | View on Google Maps |
| Spring Quality | Sodium-Chloride Simple Hot Spring (Low-Alkaline “Bijin-no-yu”) |
| Benefits | Neuralgia, muscle pain, chronic skin conditions, sensitivity to cold, and skin smoothing |
| Access | 50 min by car from New Chitose Airport; 5 min by shuttle/taxi from JR Noboribetsu Station |
| Number of Ryokans | Approximately 10-15 facilities including seaside hotels, historic inns, and day-spa centers |
| Day-trip Bathing | Abundant options including Kojohama Spa Hotel and several “sento-style” day baths |
The Healing Waters: Maritime Salt and “Silk” Textures
The waters of Kojohama are a scientific marvel, bubbling up from deep coastal fissures. Classified primarily as sodium chloride simple springs, the water is crystal clear with a faint brownish tint—evidence of its “Moor” (botanical) influence from ancient forest layers buried beneath the seabed. These “Heat Waters” create a mineral film on the skin that locks in moisture and prevents core body heat from escaping, making it a favorite for those with poor circulation. Often called the “Bihaku no Yu” (Whitening Bath), the mild alkalinity helps to gently exfoliate dead skin cells, leaving your body feeling silky and smooth immediately upon exiting. Because of the massive output (over 130 vents in the Shiraoi area), the water is used in its purest form, often referred to as “Gensen Kakenagashi” (100% natural flow).
Top 5 Recommended Ryokans
- Kojohama Spa Hotel (Renovated Heritage): A cornerstone of the town that underwent major renovations in 2024. It offers spacious family rooms with sea views and a massive bathing complex that uses three distinct spring sources.
- Hotel Izumi (Scenic/View): Perched on a hill overlooking the Pacific Ocean, this hotel is famous for its panoramic open-air baths and its connected “Park Golf” course, which is free for guests to enjoy.
- Hoshino Resorts KAI Poroto (Ultra-Luxury nearby): Located just a few kilometers away in central Shiraoi, this designer ryokan offers a high-end conceptual experience based on Ainu culture and direct access to rare moor springs.
- Aonubi Yuyu (Boutique/Traditional): A quiet seaside inn known for its exceptional seafood dinners and private bathing options, perfect for couples seeking a peaceful maritime getaway.
- Hotel Ocean (Value/Authentic): A modest, welcoming hotel that prioritizes the quality of its salt-rich baths and offers affordable seafood-centered plans including Hokkaido crab.
Must-Visit Public Baths (Soto-yu)
Kojohama is a paradise for day-trippers. The Kojohama Spa Hotel offers a popular day-pass for roughly 800 yen, providing access to their large indoor and outdoor pools. For a more local, retro experience, visit the “Kojohama Onsen Sento” facilities scattered along Route 36; these are often frequented by local fishermen and offer a glimpse into the authentic community life of the coast. For those wanting a quick break, the “Yumeguri” footbath near the visitor center is free and offers a relaxing rest for your feet while looking out toward the Noboribetsu mountains.
Walking Guide & Scenic Spots
Start with a walk along the Kojohama Beachfront, where you can see the dramatic rock formations and the “Inga-Guruma” monument. A 10-minute drive leads to Upopoy (The National Ainu Museum and Park) in central Shiraoi; this is Hokkaido’s most important cultural site, featuring a reconstructed village and world-class performances. For nature lovers, head to Lake Kuttara, which has some of the clearest caldera water in Japan and is surrounded by primary forests that change color brilliantly in autumn. In winter, the drift ice can occasionally be seen far on the horizon of the Pacific.
Local Gastronomy & Souvenirs
Kojohama is the undisputed capital of Tarako (Salted Cod Roe). The cold, nutrient-rich waters yield the highest quality roe in Japan. Visit Tarako Ya Kojohama (Kaneshime Takahashi Suisan) for their famous “Tarako Pasta” or a seafood bowl topped with fresh roe. Another must-try is Shiraoi Wagyu Beef, a luxury brand known for its deep flavor. For souvenirs, look for “Cod Roe in a Jar,” local kelp products, and hand-crafted Ainu woodwork from the gift shops at Upopoy. The “Shiraoi Burger,” made with local beef and vegetables, is a popular quick meal at roadside stations.
Cultural & Historical Context
The name “Kojohama” comes from the Ainu word kutar-un-i, meaning “place where giant knotweed grows.” The area has been inhabited by the Ainu for thousands of years, and the hot springs were utilized as spiritual sites long before Japanese settlement began in the Meiji era. The town developed rapidly as a fishing and mining hub, but today it is transitioning toward Sustainable Wellness Tourism. The connection between the Jomon-period archaeological sites nearby and the volcanic springs provides a deep historical layer to every visit.
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Practical Travel Tips
Transportation: While accessible by bus, renting a car is highly recommended to explore the coast and the inland lakes efficiently. Seasonality: Summer is great for sea views and Upopoy visits, but winter offers the best “contrast experience” where the salt-rich waters feel incredibly warm against the freezing sea air. Tattoos: Kojohama is generally more relaxed than major cities, and many facilities (like Kojohama Spa Hotel) allow guests with covered tattoos or provide private baths. Cod Roe: If buying Tarako to take home, ensure you have a cooler bag, as the fresh product requires refrigeration.
2025-2026 Latest Updates
In April 2026, Hokkaido Prefecture will introduce a new accommodation tax (100–500 yen per night), which will be used to fund local infrastructure and overtourism measures. Additionally, the “Kojohama Renovated Plaza” is scheduled to open in late 2025, offering a new hub for local seafood markets and a modern “Seaside Footbath” with free Wi-Fi for international travelers.
Safety & Manners
In the onsen, always rinse thoroughly at the washing stations while seated—standing showers can splash others in the communal area. When exploring the coastline, be aware that the Pacific tide can be very strong; stay off the breakwaters during high waves. Finally, Kojohama is a quiet fishing town; please maintain a quiet tone during your evening walks through the residential streets.
