Hirauchi Kaichū Onsen
Onsen lovers will be in heaven here. The outdoor baths are in the rocks by the sea and can only be entered at or close to low tide. You can walk to the baths from the Kaichū Onsen bus stop, but the next stop, Nishikaikon, is actually closer. From Nishikaikon, walk downhill towards the sea for about 200m and take a right at the bottom of the hill.