Nakadake Onsen (中岳温泉)

Introduction: The Secret Footbath of the Gods in the Daisetsuzan High Alpine

Deep within the heart of Daisetsuzan National Park—often called “Kamui Mintara” (The Playground of the Gods) by the Ainu—lies one of Hokkaido’s most rewarding “wild” thermal experiences: Nakadake Onsen (中岳温泉). This is not a town, nor a resort with buildings and menus; it is a raw geothermal seepage in a mountain valley, accessible only to those willing to trek through the alpine tundra. Located between the peaks of Mt. Asahi and Mt. Nakadake, this natural hot spring emerges directly into a cold mountain stream. For the international adventurer, Nakadake Onsen represents the pinnacle of “Backcountry Wellness.” Here, you can sit on volcanic stones, dangle your tired feet into a perfect mix of hot mineral water and icy snowmelt, and look out over a primeval landscape that looks exactly as it did thousands of years ago. It is a place of profound silence, high-altitude air, and the purest connection between the human spirit and the volcanic energy of the earth.

Key Information Table

The Healing Waters: A DIY Riverside Footbath

Nakadake Onsen is a geological gift for hikers. The water emerges from the rocky bank at temperatures near 60°C. Because it flows directly into a cold stream, bathers must engage in “Onsen Engineering.” You will often find small shovels left by previous hikers, allowing you to move rocks and sand to create your own “tub.” By mixing the piping hot volcanic water with the cold mountain stream, you create a customized soaking temperature. The water is rich in Sulfates and Iron, which provides an immediate soothing effect on leg muscles exhausted from climbing Hokkaido’s highest peaks. While full-body soaking is possible, it is traditionally used as an Ashiyu (Footbath) spot, providing a communal moment for hikers from all over the world to share stories while surrounded by steam and alpine flowers.

Recommended Bases & Logistics

Since you cannot stay at Nakadake Onsen, travelers use the surrounding resort villages as their base camp.

• Asahidake Onsen Area: The most popular choice. Staying at La Vista Daisetsuzan or Hotel Bear Monte allows for an early morning start on the ropeway to reach Nakadake before the afternoon clouds roll in.
• Sounkyo Onsen Area: For those doing the “Grand Traverse” (Daisetsuzan Ju-so), starting from Sounkyo and ending at Nakadake Onsen before descending to Asahidake is a classic multi-day route.
• K’s House Hokkaido (Asahidake): An excellent budget option for international backpackers and hikers who want to meet other adventurers planning the trek to Nakadake.

The Trekking Experience: The Path through the Gods’ Playground

The journey to Nakadake Onsen is as spectacular as the destination itself.
The Sugatami Loop: Most hikers take the ropeway to Sugatami Station, pass the smoking fumaroles of Mt. Asahi, and then traverse the “Susoaidaira” plateau.
Alpine Flora: In July and August, the Susoaidaira plateau is a carpet of “Chinguruma” (Aleutian avens) and “Ezo-kozakura” (primula), creating a surreal garden at 1,800 meters.
The Final Descent: The trail drops into a lush valley where the smell of sulfur and the sight of rising steam signal your arrival at Nakadake Onsen.

Local Gastronomy for Hikers: The “Summit Lunch”

There are no facilities at the onsen, so food preparation is part of the ritual.
Portable Ramen: A favorite for hikers is to use a portable gas stove to cook ramen using the cold stream water (boiled thoroughly).
Higashikawa Rice Balls (Onigiri): Before starting your hike, buy rice balls made with Higashikawa’s mineral-rich rice in the town center. They are the perfect high-energy vegan snack.
Vegetarian/Vegan Survival: Pack trail mix, local apples, and dried “Konbu” (kelp) snacks from the Asahikawa markets. Remember: Carry out all trash (Leave No Trace).

Cultural & Historical Context

For the Ainu people, the area around Mt. Asahi and Nakadake was a sacred “Kamuy-nomi” site—a place to pray to the spirits. They recognized the healing power of these wild springs long before modern hikers discovered them. During the pioneering Meiji era, the onsen served as a vital survival point for explorers mapping the interior of the island. Today, it remains a symbol of Japan’s “Mountain Onsen Culture,” where the lack of luxury is precisely what makes the experience valuable.

Practical Travel Tips for International Visitors

• Tattoo Policy: As a wild, outdoor spot, there are no restrictions on tattoos. This is one of the few places in Japan where you can soak freely regardless of ink.
• Hiking Safety: This is a high-alpine environment. Weather can change in minutes from sunshine to freezing rain/fog. Sturdy hiking boots, rain gear, and a bear bell are mandatory.
• Language Support: Signage on the trails is provided in Japanese and English. The Asahidake Visitor Center provides excellent English maps and current trail conditions.
• Best Time to Visit: Late July to mid-September. Before July, the valley is buried in snow. By October, winter conditions return.

2025-2026 Latest Updates

In 2025, the Daisetsuzan National Park authorities improved the trail markers leading to Nakadake Onsen to assist international hikers. For the 2026 season, a new “Wild Onsen Etiquette Guide” in multiple languages will be available at the ropeway station, focusing on environmental preservation and safety during “DIY” tub building.

Safety & Manners

Always wash your feet in the cold stream downstream *before* entering the hot pool to keep the mineral water clean for others. Do not use soap or shampoo—this is a protected national park. Be “Bear Aware”—this is prime brown bear territory; never leave food scraps or strong-smelling trash behind. Finally, respect the “Silent Hour”—if other hikers are present, keep conversations low to preserve the majestic silence of the high alpine.