San Antonio’s Outdoor Pools and Rock Pools: Where to Swim Laps This Summer

Swimmers are ditching indoor lanes this July for outdoor pools and natural rock pools across San Antonio, seeking relief from a heat index that hit 104 degrees on Wednesday. The San Antonio Parks and Recreation Department reported a 22 percent increase in lap-swim reservations at city-operated pools since June 1, compared to the same period in 2025.

The surge comes as gyms raise membership fees-Gold’s Gym on Broadway increased its monthly rate by $12 in April-and as residents look for affordable, socially-distanced exercise options. Lap swimming at San Antonio’s outdoor municipal pools costs just $3 per session for adults, $2 for seniors and children.

But the real draw this summer is the growing network of natural rock pools and spring-fed swimming holes within city limits. San Pedro Springs Park, at 1315 San Pedro Ave., has been a local swimming spot since the 1700s. Its limestone-lined spring-fed pool stays at a constant 72 to 74 degrees, and early-morning lap swimmers can get in 20 to 30 uninterrupted lengths before the recreational crowd arrives around 10 a.m. The pool underwent a $1.2 million renovation in 2023, adding new lane markers and a filtered circulation system.

Beyond the Concrete: Rock Pools and Natural Lanes

Comanche Park, off Hildebrand Avenue near the San Antonio River, opened two rock-pool swimming areas in March after a $2.8 million restoration project. The upper pool, fed by Comanche Springs, features a 75-foot-long natural channel that locals use for continuous lap swimming. The water temperature hovered at 68 degrees during a July 8 visit, drawing triathletes from the Alamo City Triathlon Club for weekend training sessions.

Blanco River Regional Park, about 25 minutes north of downtown, offers a mile-long stretch of river with consistent currents perfect for downstream lap swimming. The park charges $5 per vehicle on weekends. Lifeguards are on duty from 9 a.m. to 7 p.m. through Labor Day.

Not all outdoor options are natural. The city’s five outdoor competition pools-including the 50-meter Olympic pool at the San Antonio Natatorium on West Durango Boulevard-have extended morning lap hours to 8 a.m. starting July 15. The Natatorium, built for the 1968 U.S. Olympic trials, charges $4 per lap session and requires online reservations through the parks department’s website.

How to Beat the Crowds and Stay Safe

The parks department recommends booking lanes 48 hours in advance through its ActiveNet portal, as weekend slots at San Pedro Springs and Comanche Park often fill by Thursday. A 2025 study from the University of Texas Health Science Center at San Antonio found that open-water swimming in natural pools can reduce perceived exertion by 18 percent compared to chlorinated pools, due to the cooler water temperature.

Lap swimmers should arrive by 7 a.m. for the best availability at all locations. Sunscreen is mandatory-the UV index in San Antonio has exceeded 9 on 12 days so far this July. For rock pools, swim fins or pull buoys are recommended to navigate uneven rock surfaces.

For details on pool hours, fees, and reservation links, visit the San Antonio Parks and Recreation website or call 210-207-7275. Medical professionals advise consulting a doctor before starting any new exercise regimen, especially if you have a heart condition or history of heat sensitivity.