For an unique natural experience, make your way to the bubbling pools of Makino Kogen Onsen Sarasa. This place is known for its mineral-rich waters.
To explore this naturally heated water source, you'll need to find your way to Takashima. You'll find loads of other things to see in the area, such as Hakodateyama Ski Area, Metasequoia Namiki, and Kaizu Osaki.