Inside the Volcano: Restricted Trek, pH 1.7 Onsen & Caldera Winery
Kawayu onsen station
- Exclusive Off-Limits Access: Hike past boundary ropes into Mount Io’s restricted crater alongside a certified volcanic guide.
- Heat, Chemistry & Terroir: Dig for geothermal heat, bathe in pH 1.7 hot springs, and taste volcanic-soil natural wines.
- Award-Winning Nature Experience: Enjoy an exclusive, uncrowded Hokkaido itinerary recognized by Japan’s Ministry of the Environment.
Promo codes
IDR11,628 off min. IDR116,279
IDR23,256 off min. IDR232,558
IDR186,047 off min. IDR1,860,465
IDR465,116 off min. IDR4,651,163
IDR348,837 off min. IDR4,186,047
IDR162,791 off min. IDR2,323,256
IDR186,047 off min. IDR2,790,698
IDR279,070 off min. IDR4,186,047
IDR279,070 off min. IDR4,186,047
IDR116,279 off min. IDR1,860,465
IDR46,512 off min. IDR930,233
5% off min. IDR4,561,704
IDR93,023 off min. IDR2,065,116
What to expect
Follow the path of volcanic energy from its source inside Mount Io down to a glass of local wine. Begin within the off-limits crater zone, passing boundary ropes with a certified guide to hike among 1,500 active fumaroles. Next, dig into the lakeside sand at Sunayu beach with your hands to feel the rising geothermal heat, before immersing yourself in Kawayu Onsen, one of the world's most acidic hot springs (pH 1.7). The day concludes with a private tasting at Kussharo Caldera Winery, where this mineral-rich volcanic soil yields a rare, cool-climate natural wine. You will leave with a firsthand understanding of how a single living volcano shapes the landscape, the water, and the flavors of this remote corner of Hokkaido.
- The legal drinking age in Japan is age 20. Please bring a valid ID for proof of age
- Merchants can not serve alcohol to anyone who will be driving a vehicle

Meet an active volcano up close with your local guide

Compare three onsen, each from a different underground source

Bathe in Kawayu Onsen: pH 1.7, one of Japan's most acidic springs
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