Yunhai Hot Spring (中文版：雲海溫泉) is an wild hot spring in Nantou, Renai Township. It's located 1.5km upstream from Jingying Hot Spring. The water is very hot, and seeps out from the shale in several places. It's a a really amazing hot spring, you'll never want to leave.
The hike is mostly easy, but there are a four dams which need to be climbed over, one of which is a little dangerous with the current rope that's been left there. I encourage my readers to bring a strong rope of your own (10 meters) and leave it there for other people to use. You can post your good deed in the comments section below.
Yunhai Hot Spring
Nantou County, Renai Township
Hot Spring: 24.03148, 121.21491
Parking: 24.03046, 121.19768
Detailed Map: https://goo.gl/rxMnmC