Orvis Hot Springs
45 minutes away in Ridgway, Orvis is clothing-optional. I came here with my east coast wife on an early visit home, and that was, um, a problem for her (lol!). No photos, for obvious reasons. Skip the indoor pool and head straight for the "lobster pot" near the sauna if you want real heat. My favorite: the pond. Bring: water bottle, flip flops, $25 cash.
Ouray Hot Springs
Downtown in Ouray, so you can also check out the daredevils at the Ice Climbing Park. This is the family-friendly option, with big pools, mountain views, and no naked surprises. Temperatures range from warm lap lanes to 104°F soaking tubs. Great day trip to check out the town of Ouray, which is more of a throwback than Telluride these days.
Dunton Hot Springs
If you've got cash — like major cash — Dunton is the choice. Many of the rooms even have hot springs included, but will run you a solid 4-figures per night. It's about 1.5 hours away and hard to get to in winter, but awesome. Go fishing in the Dolores River just down the road. In shoulder season, you can sometimes snag a day pass (call ahead).
Rico Hot Springs
I can't say too much...but near Rico, there is a hot springs spot on the Dolores River. Look for locals. Be cool.
Piedra River Hot Springs
Worth the drive (2+ hours) for the most natural experience around. A 1.5-mile hike leads to riverside pools that are rebuilt constantly by visitors after floods. In winter, snowshoes and avalanche awareness make it a magical (and safe) soak. Look for the parking lot on Hwy 160 between mile markers 22–23.
Pagosa Hot Springs
The grandaddy of hot springs in Southwest Colorado. Built out, touristy, and pretty nice for a day — 3+ hours from Telluride. Jump into the San Juan River to cool off, or try to catch some trout in town. Meander made the NYT's 50 Best Restaurants in the US a few years back, so check it out (and staying at the hot springs gets you free entry).
Happy soaking! Don't forget water...