Balneario Municipal Piray Guazú is a popular municipal swimming and camping area situated on the banks of the Arroyo Piray Guazú, about 9 kilometers from the city of Eldorado in Misiones, Argentina.

The arroyo itself — whose Guaraní name means "river of the fish" — draws large crowds during the summer months. The grounds accommodate up to 250 tents and are well shaded with trees.

Facilities include grills, restrooms, a snack bar, a natural swimming area, and a playground. Lifeguards and an ambulance service are on duty during the season.

On weekends and holidays, a bus service runs between Avenida Córdoba (Km 9) in Eldorado and the balneario, making it accessible without a private vehicle.