This long thin park in the middle of Jiaoxi, not far from the train station, is the source of the famous local hot spring. An open stream of hot spring water runs through the park, and both tourists and locals come here to soak their feet in the hot spring water and chat. There are also several pools for foot soaking. Unlike the hot spring park in Beitou, this water is clean (the water running through the park in Beitou is discharge from the surrounding hot spring - you might occasionally see a turd floating downstream). You can walk upstream and see where the hot spring comes out of the ground, so the water here is pristine.
Besides foot soaking, in the evenings people gather here to walk along the boardwalk which runs the length of the park. There are a few vendors to the side where you can buy local produce (guavas, kumquats, and so on) and also some snacks. On weekdays this park is fairly quiet, but on weekends there are quite a few people here. The number of vendors increases considerably and on one side the place becomes a bit like a night market.
There are two places to bathe in the hot spring water in the park. One is the decrepit old shack in toward the west end of the park. This is a communal naked hot spring for men only. In fact, the only people who go here are old lmen from Jiaoxi. It's free, but that's the only good thing you can say about this place. The patrons are pretty creepy and the unpleasant atmosphere scares off most people. But if you're absolutely determined to get a free hot spring bath, this is the place.
The other option is the new communcal hot spring building on the far side of the park. This is an extremely beautiful building. In fact, it's something of an architectural gem. The interior is all wood - even the hot spring pools are lined with wood.
Admission is only NT 80, and senior citizens (over 65) get in for just NT 40. There are two communal naked pools - with men and women on different sides. Considering how nice this place is, the low admission price is a huge bargain. As a result, this hot spring is much too popular. On cold days you can expect a crowd, even during the week. On weekends don't even think about it - this place will be bursting at the seams.
Another problem is that unlike every other communal hot spring I've ever been to, the temperature isn't centrally regulated. Instead the patrons can determine how much hot and cold water goes into pool. There's ALWAYS at least one crazy old guy who likes his bath boiling hot, so the temperature is usually 43 degrees - far beyond most people's comfort zone. I brought an American friend here who had never been to a hot spring before. He ended up on the side of the pool curled up in a fetal position like a burn victim.
At night, there are two cafes at each end of the park. The one of the east serves both drinks and food - mostly Yilan specialties made with the local scallion and other vegetables. The one on the west serves only drinks. However, both serve freshly brewed microbrewery beer. I've tasted the dark malt, which I liked. I wasn't crazy about the wheat beer. I thought it had a funny taste. I have yet to try the others beers. One of their beers is brewed with seaweed, which I haven't dared to try. If you've always wanted to try seaweed flavored beer, this is your big chance.
In the evenings, there is often a singer with guitar singing old Taiwanese songs for tips at one cafe or the other. Even on the hottest days, there's a cool breeze here in the evening. A foot bath, beer, and quiet music is a pleasant way to end the day.