The Three Ancient Springs (日本三古湯, Nihon San Kotō) are a group of ancient onsen in Japan.

According to the Nihon Shoki and Fudoki, both from the eighth century, they are:

• Dōgo Onsen, Ehime Prefecture
• Arima Onsen, Hyōgo Prefecture
• Nanki-Shirahama Onsen, Wakayama Prefecture

The tenth century Engishiki gives a slightly different list:

• Dōgo Onsen, Ehime Prefecture
• Arima Onsen, Hyōgo Prefecture
• Iwaki Yumoto Onsen, Fukushima Prefecture