The world’s biggest pool by volume is the San Alfonso del Mar seawater pool, located in Algarrobo on Chile’s central Pacific coast. Opened in 2006, it holds roughly 250 million liters (66 million gallons) of seawater and covers about 8 hectares (20 acres). This answer explains where it is, how it functions, its verified dimensions, and why it remains the largest by volume as an evergreen reference for travelers, engineers, and curious readers.
Exact Location and Geography
San Alfonso del Mar is in Algarrobo, Valparaíso Region, Chile, approximately 100 kilometers (62 miles) west of Santiago and near the tourist town of Zapallar. The pool sits on a coastal strip between the Andes and the Pacific, using its shoreline position to draw in and maintain seawater. The site’s latitude of about 32.9° S positions it in a climatic zone that supports reliable sunshine, which helps reduce evaporation and maintain comfortable water temperatures for swimmers.
Coordinates and Region Details
- GPS coordinates: Approximately 33.04° S, 71.52° W
- Region: Valparaíso Region, Chile
- Nearest major city: Santiago (about 100 km inland)
Size and Capacity by the Numbers
Recognition as the largest pool rests on its extraordinary volume and surface area, far beyond typical municipal or resort pools. The pool’s reported 250 million liters (66 million gallons) of water would take roughly 1,000 average backyard pools to equal. Its immense scale is maintained by a sophisticated computer-controlled system that pumps and treats seawater continuously.
Key Dimensions at a Glance
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Volume | Approximately 250 million liters (66 million gallons) | Engineer reports and resort data |
| Surface Area | About 8 hectares (20 acres) | Resort specifications and coverage notes |
| Length | Up to 1,013 meters (3,324 feet) | Published pool dimensions |
| Maximum Depth | Approximately 3.5 meters (11.5 feet) | Design specifications |
| Region | Algarrobo, Valparaíso Region, Chile | Geographic records and tourism sources |
How the Pool Works and Is Maintained
Unlike a stagnant decorative pool, San Alfonso del Mar operates like a controlled body of seawater. It draws Pacific seawater, passes it through filters and disinfectant systems, and maintains consistent quality for bathers. A computer system manages inflow and outflow, compensating for tides and weather. Because it is open to the air and subject to evaporation, periodic replenishment with fresh seawater is necessary to stabilize salinity and volume.
Operational Highlights
- Seawater intake and continuous filtration
- Computer-controlled flow and level management
- Chlorination and treatment to meet recreational water standards
- Regular monitoring for temperature and salinity
Context: How It Compares to Other Large Pools
While other pools may claim length or surface area records, San Alfonso del Mar holds the title for total volume, which accounts for both surface area and depth. Some hotel lobbies or public pools are long and narrow; others are wide but shallow. This pool’s combination of size, depth, and seawater content is unusual and carefully engineered to remain stable across seasons and tides.
- Largest by volume: San Alfonso del Mar (250 million liters)
- Longest pools may exceed its length but hold far less water
- Typical municipal pools are orders of magnitude smaller
Construction Purpose and Uses
Originally conceived as a way to provide chilled seawater for nearby communities, the pool also became a landmark destination for tourists seeking a novel seaside experience. Its transparent, lagoon-like design allows visitors to swim in the Pacific’s water without the waves and chill of open surf. Beyond recreation, it showcases how large-scale water management can be combined with coastal tourism in an environmentally sensitive region.
Primary Uses
- Public swimming and recreational activity
- Tourist attraction and regional landmark
- Demonstration of engineering and water treatment at scale
Environmental and Climatic Considerations
In a coastal desert climate, managing a pool of this size requires attention to evaporation, water temperature, and energy use. The pool uses a combination of depth, partial covering, and chemical treatment to reduce losses. Local winds and fog can affect evaporation rates, but careful design helps preserve water quality and minimize waste. While not a freshwater facility, its reliance on seawater reduces the strain on local freshwater resources, a key consideration in arid regions.
Environmental Factors
- Low rainfall limits freshwater inputs
- High evaporation risk managed by depth and treatment
- Seawater sourcing avoids local freshwater consumption
Frequently Asked Questions
Below are concise answers to common questions about the world’s largest pool by volume, its location, and how it compares to other notable aquatic spaces.
- Where is the biggest pool in the world located? The largest swimming pool by volume is San Alfonso del Sea, located in Algarrobo, Chile.
- What makes it the largest? Its volume of roughly 250 million liters (66 million gallons) surpasses other pools by a wide margin.
- Can the public swim there? Yes, it is open to visitors as a recreational pool and tourist attraction.
- How was such a large pool built? It uses engineered seawater intake, continuous filtration, and computer-controlled flow systems to maintain stability.
- Are there larger pools by length or surface area? Some pools are longer or have greater surface area, but San Alfonso del Mar remains the largest by total water volume.
