Termales del Otoño is the most accessible thermal-spring complex from Manizales — a hotel and spa on the road into Los Nevados National Park, about 30 minutes from the city. Three outdoor pools at different temperatures are fed by mineral-rich water from the Nevado del Ruiz volcanic system.
The setting is forested and quiet, and the pools stay open into the evening. Day passes are reasonable. Combine with a morning walk in the lower páramo if you are heading further into the park.