Most of us picture a backyard rectangle or a hotel lap pool when we hear the word “pool.” But around the world, engineers and resorts have built swimming pools so vast they are measured in acres rather than feet, hold tens of millions of gallons of water, and in some cases need boats to cross. Some hold official world records; others are simply jaw-dropping feats of design.
From a man-made lagoon longer than 20 football fields to a desert resort pool the size of a small lake, here are the ten biggest swimming pools in the world – ranked roughly by surface area – along with where to find them and what makes each one a record-breaker.
Fun Facts About the World’s Biggest Pools
The largest swimming pool in the world is the Citystars lagoon in Sharm El Sheikh, Egypt, which holds the current Guinness World Record after overtaking Chile’s San Alfonso del Mar in 2015.
Many of these giants are “crystal lagoons” — built with technology invented by Chilean biochemist Fernando Fischmann, first used at San Alfonso del Mar.
The technology is surprisingly efficient, using up to 100 times fewer chemicals and only about 2% of the energy of a conventional pool filtration system of the same size.
Some pools are so vast that visitors sail small boats, kayak, and paddleboard across them rather than simply swim.
Japan’s former Seagaia Ocean Dome was the largest indoor pool ever built, a climate-controlled beach under a retractable roof — just a short walk from the real ocean.
The crystal-clear lagoon at the San Alfonso del Mar resort on Chile’s Pacific coast is the most famous giant pool on Earth, and for years it held the Guinness World Record for the largest swimming pool. It stretches roughly 1,013 meters (about 3,324 feet) from end to end – longer than 20 football fields – covers around 20 acres, and holds an astonishing 66 million gallons of seawater.
The pool is so large that visitors sail small boats and kayaks across it. Filtered seawater is pumped straight from the adjacent ocean, keeping the lagoon turquoise and warmer than the cold Pacific waves just beyond the resort.
2. Citystars Sharm El Sheikh – Sharm El Sheikh, Egypt
Opened in 2015, the lagoon at the Citystars resort in Sharm El Sheikh, Egypt, took the Guinness World Record from San Alfonso del Mar for the largest pool by surface area. This man-made crystal lagoon covers around 23 acres (about 96,000 square meters) and winds through the desert resort like a private blue river.
Lined with white sand and ringed by villas, the lagoon is shallow enough for swimming and water sports throughout, making it as much a beach substitute as a pool in a region where the Red Sea is a short drive away.
3. Mahasamutr Luxury Lagoon – Hua Hin, Thailand
Illustrative photo of a luxury resort lagoon (not the lagoon itself). Source: Prasertsak Naksakul on Pexels
Mahasamutr, near the seaside town of Hua Hin, is billed as the largest crystal lagoon in Asia. The turquoise centerpiece of an exclusive villa community covers around 17 acres (roughly 72,000 square meters) and is surrounded by private homes whose owners can swim, paddleboard and kayak right outside their door.
Like other crystal lagoons, it uses an efficient filtration technology that keeps the enormous body of water clear while using a fraction of the chemicals and energy a conventional pool of that size would need.
4. Dreamworld Fun Lagoon – Karachi, Pakistan
Illustrative photo of a water-park pool (not the lagoon itself). Source: Erik Mclean on Pexels
The Fun Lagoon at the Dreamworld Resort outside Karachi is one of the largest swimming pools in South Asia. The sprawling free-form pool covers several acres and is a centerpiece of the resort’s water park, complete with islands, bridges and slides scattered across its surface.
Because it is built as a leisure pool rather than a swimming lane, much of the lagoon is shallow, making it popular with families escaping the city’s heat.
5. Treasure Bay Bintan – Bintan, Indonesia
Illustrative photo of a resort lagoon (not the venue itself). Source: Danor on Pixabay
Southeast Asia’s largest man-made seawater lagoon anchors Treasure Bay Bintan, a sprawling resort on Indonesia’s Bintan Island just across the strait from Singapore. The 6.3-hectare crystal lagoon holds around 115 million litres of filtered seawater – roughly the volume of fifty Olympic pools.
Opened in 2015 as the centrepiece of a multi-billion-dollar development, the lagoon is built for kayaking, sailing and swimming, and proved that the giant-lagoon concept pioneered in Chile could thrive in the tropics.
The Seagaia Ocean Dome in Miyazaki was once the world’s largest indoor water park and pool, holding the record for the biggest indoor pool ever built. The retractable-roof dome measured roughly 300 meters long and 100 meters wide, enclosed a permanently warm, sunny climate, and featured a vast artificial beach with a wave machine and even a fake volcano.
The Ocean Dome closed in 2007, but it remains the benchmark for indoor mega-pools and an icon of 1990s engineering ambition.
China’s summer water parks are famous for enormous wave pools packed shoulder-to-shoulder on the hottest days, and Hangzhou’s is among the big draws in the country’s east. Its wide wave basin and powerful surf machine can make the water feel more like an inland sea than a swimming pool.
China is home to some of the most crowded pools on earth – from the “Dead Sea of China” in Sichuan to giant parks in Beijing and Shanghai – and Hangzhou’s wave pool is a vivid reminder of just how big, and how busy, a public pool can get.
8. The Lagoon at Windsong Ranch – Prosper, Texas, USA
North Texas got its own slice of the Caribbean when The Lagoon at Windsong Ranch opened in the master-planned community of Prosper, near Dallas. The five-acre crystalline lagoon reaches about eight feet at its deepest and is ringed by white-sand beach.
Built with Crystal Lagoons technology, it uses a fraction of the chemicals and energy of a conventional pool, and hosts paddleboarding, kayaking and swimming for residents far from any coastline.
9. The Lagoon at Epperson – Wesley Chapel, Florida, USA
The Crystal Lagoon at Epperson, north of Tampa, was the first of its kind in the United States and remains one of the largest. The 7-acre lagoon holds millions of gallons of clear blue water and is the centerpiece of a residential community, offering kayaking, paddleboarding, a swim-up bar and a sandy beach.
Its success kicked off a wave of similar lagoon communities across the Sun Belt, bringing the giant-pool trend to American suburbs.
10. The Lagoon at Mirada – San Antonio, Florida, USA
Illustrative photo of a resort lagoon (not the venue itself). Source: HarshLight on Flickr | CC BY 2.0
Rounding out the list is the largest man-made lagoon in the United States: the fifteen-acre Lagoon at Mirada in San Antonio, Florida, north of Tampa. Opened in 2023 with more than thirty million gallons of crystal-clear water, it delivers a full beach day – white sand, water slides and swim-up bars – nowhere near an actual coastline.
From a record-setting lagoon in Chile to suburban beaches in Florida, the world’s biggest swimming pools prove that with enough ambition, you can bring the sea almost anywhere.
FAQ: The World’s Biggest Swimming Pools
What is the biggest swimming pool in the world?
The current record-holder is the crystal lagoon at the Citystars resort in Sharm El Sheikh, Egypt, which took the Guinness World Record for the largest pool by surface area in 2015. Before that, the title belonged to the famous San Alfonso del Mar lagoon on the coast of Chile, which is more than 1,000 metres long.
How big is the San Alfonso del Mar pool?
The lagoon at San Alfonso del Mar in Algarrobo, Chile, stretches roughly 1,013 metres (about 3,320 feet) from end to end, covers around 20 acres, and holds about 66 million gallons of filtered seawater. It is so large that guests sail small boats and kayaks across it.
What are “crystal lagoons”?
Crystal lagoons are enormous man-made pools built with a patented technology invented by Chilean biochemist Fernando Fischmann. The system keeps huge bodies of water crystal-clear while using far fewer chemicals and much less energy than a conventional pool of the same size, which is why the concept has spread from Chile to resorts and neighborhoods around the world.
Where is the biggest pool in the United States?
The largest man-made lagoon in the United States is the Lagoon at Mirada in San Antonio, Florida, north of Tampa, which covers about 15 acres and holds more than 30 million gallons of water. The nearby Lagoon at Epperson was the first crystal lagoon built in the US.
Can you actually swim in these giant pools?
Yes. Most of these lagoons are designed for recreation, with shallow areas, sandy beaches, and calm, clear water for swimming, kayaking, paddleboarding, and sailing. Many belong to resorts or residential communities, so access can be limited to guests or residents.
Was there ever a bigger indoor pool?
Yes. Japan’s Seagaia Ocean Dome in Miyazaki was once the largest indoor water park and pool in the world, complete with an artificial beach, a wave machine, and a retractable roof. It closed in 2007 and was later demolished, but it remains the benchmark for indoor mega-pools.
Why do desert and inland resorts build these lagoons?
Giant crystal lagoons let developers create a beach-style experience far from any coast — in deserts, suburbs, and inland communities. Because the technology is water- and energy-efficient, resorts from Egypt to Texas use them as a centerpiece amenity that gives residents and guests turquoise water and sandy beaches without the sea.
