Onoaida Onsen
According to local legend, a hunter discovered Onoaida Onsen when he saw a deer healing its wounds in the hot springs. Today Onoaida Onsen is most popular with locals and with mountain climbers hiking the nearby two-hour trail leading to the Janokuchi Waterfall.
At around 46°C, these are the hottest springs on Yakushima. They can also be enjoyed year-round as they are located indoors. There are no towels, soap, or shampoo, though, so visitors should make sure to bring their own supplies. The bath is open daily from 7:00 am to 9:30 pm (Mondays from 12:00 pm). It costs 100 yen for children up to elementary school age (toddlers go free), or 200 yen for adults.