San Alfonso del Mar: The World’s Biggest Pool Resort?

 

The massive lagoon at the San Alfonso del Mar resort in Algarrobo remains one of Chile’s most iconic landmarks, famously stretching over 1,013 meters in length. Designed to solve the problem of the central coast’s freezing and dangerous Pacific waters, the pool provides a controlled environment where the water is filtered and warmed to a comfortable 26°C. This architectural feat was made possible through specialized technology that keeps the water a vivid turquoise, contrasting sharply with the dark, choppy ocean just a few meters away.

Regarding its current status, the pool is still in use, but there are significant misconceptions about how it functions for the public. It is important to note that the lagoon is not a public water park; it is a private facility reserved exclusively for the residents and guests of the resort's various apartment towers. Even for those staying there, the lagoon is primarily utilized for water sports like kayaking and sailing due to its sheer scale. In fact, many of the cordoned-off areas are specifically for boating, while designated smaller sections are used for actual swimming to ensure lifeguard safety and easier maintenance.

One reason people often think the pool is "closed" or "not in use" is due to the strict seasonal and maintenance schedules. During the Chilean winter, the lagoon may look quiet as outdoor activity drops, and the resort focuses on the heated indoor beach—a glass-pyramid structure that allows for swimming year-round. Additionally, because the maintenance costs are astronomical, the resort has historically faced legal and financial debates among the homeowners' association regarding the upkeep of such a massive body of water, leading to occasional rumors of its closure.

Despite no longer being the absolute largest in the world—a title surpassed by a lagoon in Egypt—San Alfonso del Mar remains fully operational as a centerpiece of Chilean tourism. It continues to serve as a high-end residential hub, though casual travelers should be aware that they cannot simply pay a day-use fee to swim; they must book an stay in one of the private rentals to experience the "crystal" waters firsthand.