San Alfonso del Mar is a resort located in Algarrobo, Chile frequently noted because of its 1,000-meter long, 19-acre outdoor pool, which holds a Guinness world record[1] as the largest in the world. The resort's large pool utilizes a technology developed by the Chilean company Crystal Lagoons, which uses water pumped from the Pacific Ocean, that is then filtered and treated for supply to the pool.

It has been reported to have a depth of 35 meters (115 feet)[2][3] which would make it the world's deepest pool, however this appears to stem from confusion over it being "transparent to a depth of 35 meters".