Laguna Don Tomás is an urban lagoon situated within the Parque Recreativo Don Tomás in Santa Rosa, the capital of La Pampa province, Argentina. The park covers approximately 500 hectares and serves as the city's primary recreational space. The lagoon is named in honor of Don Tomás Mason, one of the founders of Santa Rosa.

For paddlers, the lagoon supports kayaking, canoeing, windsurfing, water skiing, and motorized watercraft. The Club Náutico La Pampa Río Atuel operates on the lagoon and offers kayak lessons for all ages and experience levels, from beginners to those with prior paddling experience. The club also functions as a boat storage facility. A recently restored dock (muelle) is available, and pedal boats and a catamaran are among the watercraft options at the site. The Santa Rosa municipality has undertaken infrastructure improvements to the park, including the dock restoration, making it a more developed paddling environment.

The lagoon is entirely urban in character, set within a well-maintained public park. A 5-kilometer perimeter path runs along the water's edge, and three islands are accessible by bridges. Landmarks visible from the water include a lighthouse and a viewpoint known as the Cruz. The park is open daily from 08:00 to 18:00, though hours may vary seasonally.

Water quality warrants some caution. The lagoon receives runoff from various urban sources, and local accounts question the advisability of consuming fish caught there, suggesting the water may carry urban contaminants. Paddlers should be aware of the mixed-use nature of the lagoon, which accommodates motorized watercraft alongside human-powered craft, requiring attention to vessel traffic.

The park is heavily used by the public, particularly on weekends, when families, joggers, cyclists, and anglers share the space. The park's entrance is on Avenida San Martín and the exit on Avenida Uruguay. City bus lines 4 and 6 serve the area, and the park is walkable from the city center.