Thermal Hot Springs at La Gruta

La Gruta is a 12-acre thermal spring park on the road between San Miguel de Allende and Dolores Hidalgo in Guanajuato state, built around a chain of interconnected mineral pools fed by a natural hot spring. The best-known feature is a short underground tunnel that leads swimmers to a domed cavern pool where a warm spring jet falls from the ceiling. The park requires no particular fitness or swimming skill beyond basic comfort in water, and pools range from wading depth to chest depth, making it accessible to most ages, though very young children should be supervised closely in the tunnel section. No specialised equipment is provided or required beyond swimwear, a towel, and sandals; lockers and changing rooms are available on site for a small additional fee. La Gruta Spa, the family-run operator, maintains lifeguards at the main pools and posts capacity limits on the busiest weekends and holiday periods. The mineral water stays around 38-40°C year-round, so the park operates in all seasons, but the calmer, cooler winter mornings from October to February are considered the most comfortable time to visit, since the contrast between the warm pools and cool air is most pleasant. The park closes on Tuesdays for maintenance and is busiest on weekends, when arriving soon after the 9:00 AM opening avoids the largest crowds.