Shuzenji Onsen is a geothermal spring system in the Tagata District of Shizuoka Prefecture, Japan, in the central region of Izu Peninsula.

The hot springs have been used for over fourteen centuries^[2] for their therapeutic properties.^[3] Folklore tales describe the discovery and founding of the hot springs by Kobo Daishi (774-835), a Buddhist monk who probed at the rocks in the river with his walking stick (tokko) releasing the hot spring water.^[4] The historical town that was built up around the geothermal system was also called Shuzenji, however it has since merged into the city of Izu.

Tokko-no-yu is the best known hot spring in the system; it is located between the banks of the Katsura River in the middle of Shuzen town. A small rustic open-air public bath house has been built above the spring containing an ashiyu or foot spa.^[2][5] Kawara-no-yu is a hot spring in the system that is used as a public foot bath; it is located at the riverside.^[6] There are numerous commercial spa hotels and historic ryokan in the area, as well as Hakoyu, the public bathhouse.^[7]

The onsen system is part of the Amagi volcanic mountain range.^[8] In Japan, more than 27,000 hot spring sources exist, many of which, including Shuzenji Onsen have been developed into onsen towns.^[3]

• List of hot springs in Japan
• List of hot springs in the world