What Is the World’s Biggest Swimming Pool
The world’s biggest swimming pool is the San Alfonso del Mar Seawater Pool in Algarrobo, Chile. It holds approximately 250 million liters (66 million gallons) of seawater and measures about 1,013 meters (3,324 feet) in length, with a surface area of 8 hectares (20 acres) and a maximum depth of 11.5 feet (3.5 meters). Built in 2015 and verified by Guinness World Records, it is a saltwater recreational pool using natural ocean water and advanced filtration to maintain clarity. Unlike hotel or resort pools, it functions as a public venue for swimming, kayaking, and bodyboarding in a controlled coastal environment.
Key Dimensions at a Glance
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Location | Algarrobo, Chile (San Alfonso del Mar resort area) | Published coordinates and resort records |
| Length | 1,013 meters (3,324 feet) | Guinness World Records 2015 |
| Surface area | 8 hectares (20 acres) | Operator specifications and media verification |
| Volume | ~250 million liters (66 million gallons) | San Alfonso del Mar technical documentation |
| Max depth | 11.5 feet (3.5 meters) | On-site surveys and published data |
| Pool type | Seawater, lagoon-style | Operator and news reports |
| Year opened | 2015 | Guinness record date and launch announcements |
Design and Engineering Choices
San Alfonso del Mar was engineered to minimize wave action and maximize still water, using barriers and carefully calculated depths. The pool draws in actual seawater from the Pacific, which is then filtered and treated to maintain visibility and hygiene. Its lagoon design reduces strong currents, making it suitable for recreational swimming, paddle sports, and tourism. The scale required robust coastal construction methods to withstand local seismic and weather conditions, a notable distinction from conventional pool builds.
Operational and Public Use
As a public recreational lagoon, the pool offers swimming, kayaking, and bodyboarding, functioning partly as a coastal water park. Lifeguard stations, measured water quality protocols, and regulated access help ensure safety given its size and shallow depth. Because it uses natural seawater, the site balances tourism appeal with environmental considerations around water intake and ecosystem impact. Visitors can experience open-water swimming in a controlled setting, which differentiates it from traditional chlorinated pools.
How It Compares to Other Large Pools
Most other large pools, such as the Nemo 33 in Brussels or deep hotel pools, are smaller in either volume or surface area and often serve specialized diving or training purposes. San Alfonso del Mar’s combination of length, surface area, and public recreational use is unusual, making it the benchmark for the world’s biggest swimming pool by capacity and dimensions. Earlier contenders like the Moscow State Pool or city lakeside facilities typically differ in structure and intended use, reinforcing the specificity of San Alfonso del Mar’s record.
Common Misconceptions Clarified
- It is not an abandoned or unfinished project; it remains an operational public lagoon.
- It is not a natural lake; it is a purpose-built seawater pool with filtration and management systems.
- It is not primarily a competition venue; it is designed for recreation, tourism, and open-water experience.
- The record focuses on dimensions and volume, not on water temperature, amenities, or visitor numbers.
What This Record Means Going Forward
As an evergreen record, the status of the world’s biggest swimming pool depends on measurable dimensions rather than temporary popularity or short-term novelty. Unless a larger seawater pool is constructed and verified, San Alfonso del Mar will remain the benchmark for size and volume in recreational lagoon design. Updates would require new construction, official measurement, and independent confirmation to alter this status.