Onuma Onsen (大沼温泉)

Onuma Onsen: An Ethereal Sanctuary of Volcanic Lakes and Alpine Majesty

Onuma Onsen is a destination where the landscape itself tells a story of cosmic upheaval and natural rebirth. Located within the Onuma Quasi-National Park in southern Hokkaido, this hot spring area is framed by the dramatic, jagged silhouette of Mt. Komagatake and the tranquil waters of Lakes Onuma, Konuma, and Junsainuma. Formed by ancient eruptions that dammed the local rivers, the park’s 126 islands create a “Japanese garden” on a continental scale. For the international traveler, Onuma offers a sophisticated blend of rustic wilderness and European-style resort luxury. Whether you are cycling the 14-kilometer lakeside circuit, paddling a canoe through mirrored waters, or soaking in thermal pools as the autumn leaves create a fiery canopy, Onuma provides a meditative escape that feels light-years away from the neon glow of the cities.

Key Information

The Healing Waters: Volcanic Purity and Metasilicic Acid

The waters of Onuma are a gift from the subterranean heat of Mt. Komagatake, an active volcano that continues to vent steam from its summit. Scientifically, the springs are classified as alkaline simple hot springs. These waters are noted for their “gentle” profile, featuring low osmotic pressure that is easy on the skin and perfect for guests with sensitive constitutions or families with young children. The springs are rich in metasilicic acid, a natural compound prized in Japan as a “skin-beautifying” agent that helps condition the skin’s surface and lock in moisture. Unlike the sulfur-heavy baths of northern Hokkaido, the transparency and lack of strong odors at Onuma allow for a meditative soak that focuses on the sensory connection to the surrounding birch and spruce forests.

Top 5 Recommended Ryokans

• Hakodate Onuma Tsuruga Resort EPUY (Ultra-Luxury/Gourmet): A high-concept auberge focused on “the blossom in the forest.” Every stay is defined by exquisite French cuisine using ingredients from within a 50-mile radius. Many rooms feature private outdoor baths with garden views.
• Hakodate Onuma Prince Hotel (Scale/Nature): An expansive resort property featuring its own golf course and a stunning open-air bath that overlooks a pond where wild birds gather. It offers free shuttle services from the Shinkansen station.
• Miraino Yado Mizunoto (Boutique/Nature): A quiet, nature-oriented lodge featuring loft-style rooms and private wood-burning fireplaces. It emphasizes a “oneness with nature” and offers private bathing sessions.
• Station Hotel Asahiya (Historic/Authentic): Located directly in front of the station, this historic inn provides traditional Japanese hospitality and access to the town’s most classic mineral sources. It is favored by hikers and railway enthusiasts.
• Pension Kaza (Cozy/Family): A charming guesthouse located on the Konuma walking path. Known for its personalized nature tours and home-cooked meals featuring local Nanae produce.

Must-Visit Public Baths (Soto-yu)

Onuma prioritizes the “resort-spa” experience, so most bathing takes place within its prestigious hotels. However, the Hakodate-Onuma Prince Hotel offers a popular day-trip bathing pass for approximately 1,200 yen, allowing non-guests to experience their legendary rock-lined outdoor pools. For a quick and free experience, the Onuma International Communication Plaza (next to the station) provides a “Hand Bath” (Te-ayu) where you can feel the warmth of the volcanic springs while gathering travel pamphlets and local maps.

Walking Guide & Scenic Spots

The Island Hopping Trail is a must; this 15-to-50-minute walk takes you across series of bridges connecting the islets of Lake Onuma, offering the best angles of Mt. Komagatake’s reflection. For a more active adventure, rent a bicycle near the station and conquer the 14km Lake Circuit, which winds through primeval forests and quiet wetlands. In winter, the frozen lake surface becomes a playground for ice fishing (smelt) and snowshoeing tours that lead to hidden “Ice Bubbles” trapped in the clear lake ice. For the most iconic photo, head to the Yama-no-Koshi Viewpoint at dawn during the autumn foliage peak in late October.

Local Gastronomy & Souvenirs

The culinary icon of the town is Onuma Dango from the legendary shop Numanoya (founded in 1905). These tiny rice dumplings come in soy sauce, sesame, and red bean flavors, representing the lakes and islands of the park. For lunch, try Onuma Beef at “Lumber House”—it is lean, tender, and raised right at the foot of the mountain. Also, don’t miss the Onuma Craft Beer, brewed with alkaline ionized water. Souvenirs to look for include Nanae Apples (the first place in Japan where Western apples were grown) and Ainu woodcarvings from local artisans.

Cultural & Historical Context

The Ainu people have long revered Mt. Komagatake as a deity, calling the area Porot-un-nai. In 1915, Onuma was selected as one of the “New Three Views of Japan,” a designation that catalyzed its development into an international resort. The park’s design was perfected by Dr. Seiroku Honda, the father of Japanese forestry, who emphasized preserving the “wild asymmetry” of the volcanic debris. Today, the town is a leader in Eco-Tourism, maintaining a strict balance between human recreation and the protection of rare species like the white-tailed eagle.

Practical Travel Tips

Transportation: If you are arriving by Shinkansen at Shin-Hakodate-Hokuto Station, use the free shuttle buses provided by the major hotels; they must be booked 3-5 days in advance. Seasonality: Mid-October for autumn colors and early February for the Ice Festival are peak periods; book your room at least 4 months ahead. Cash: While EPUY and the Prince Hotel are card-friendly, the famous dango shop Numanoya and local bicycle rentals primarily require Japanese Yen. Tattoos: Larger resorts like the Prince Hotel may require covers in communal baths; EPUY’s private in-room baths are the best choice for heavily tattooed travelers.

2025-2026 Latest Updates

The Onuma Hakodate Snow and Ice Festival 2026 is scheduled for the first weekend of February, featuring a massive ice slide and nightly “Fire and Ice” illumination. Furthermore, Tsuruga Resort EPUY has announced a new “Forest Bathing & Stargazing” program for the 2025 summer season, utilizing high-powered telescopes on their newly renovated terrace for international guests.

Safety & Manners

When walking the island trails, stay on the designated paths; the soil near the lake can be unstable due to volcanic sediment. In the onsen, always sit on the stool while washing your body to avoid splashing others—this is basic etiquette in Hokkaido’s refined resorts. Finally, please do not feed the local foxes or swans, as they are part of a strictly managed National Park ecosystem. Take all trash back to your hotel or the train station.