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What is the clearest ocean water to swim in?

What is the clearest ocean water to swim in?

When looking for the clearest ocean water to take a swim in, there are a few key factors to consider. The clarity of the water depends on the levels of plankton, sediment, and pollution present. Areas with less of these contaminants tend to have clearer water that allows visibility to greater depths. Other considerations include temperature, currents, marine life presence, and accessibility.

Plankton Levels

Plankton are microscopic organisms that float freely in ocean waters. When plankton levels are high, the water takes on a greenish hue and clarity decreases. Places that have lower plankton counts generally have clearer ocean water. This includes ocean areas far from coastlines, which tend to have fewer nutrients that feed plankton growth. The clearest open ocean regions are found in the tropics, where warmer waters discourage plankton accumulation.


Sediment refers to particles of sand, silt, and minerals suspended within the water. Areas near river mouths and coastlines tend to have higher sediment levels that reduce visibility. The clearest waters are found further offshore and away from inputs of sand and soil. Sediment levels also decline away from seafloors that are churned up by currents, waves, or tides. The calmest conditions allow particles to sink and clarity to improve.


Pollution from human activities can greatly diminish water clarity. Runoff from agricultural, industrial, and urban areas introduces chemicals, trash, and excess nutrients into coastal waters. Sewage dumping also dirty ocean waters. The clearest swimming spots are found in remote areas away from human development. Uninhabited small islands, marine reserves, and protected areas offer refuge from pollution.


Colder waters often appear cleaner because visible light travels farther through them. Cooler oceans in higher latitudes or deeper areas transmit light more efficiently. Tropical waters near the surface absorb more sunlight, reducing visibility. However, temperature alone does not dictate clarity. Some tropical diving spots still have excellent underwater views due to other favorable conditions.


Areas with strong currents and mixing have lower clarity than calm seas. The churning effect of currents sweeps up bottom sediment and distributes plankton. Locations with minimal current flows allow particles to settle and water transparency to increase. Still conditions commonly occur around sheltered bays, inlets, lagoons, and isolated atolls.

Marine Life

An abundance of marine life can impact water clarity in positive and negative ways. Plankton blooms reduce visibility, but populations of filter feeders like clams and sponges help clean the water through their filtration activities. Meanwhile, reef ecosystems and kelp forests provide structure and shoreline protection that allow clarity to improve. Barren sandy areas sometimes have less sea life but more sediments that reduce transparency.


The most breathtakingly clear waters are not always the most accessible for swimming and exploration. Remote coral reefs and uninhabited islands offer pristine conditions but may require an expensive private yacht charter to reach. Some compromise between clarity and convenience is generally needed when choosing the optimal spot. Protected marine areas close to shore often provide the best combination of clear waters and easy access.

The Clearest Ocean Regions

Based on the factors above, here are some of the clearest ocean water regions for swimming and snorkeling:

Location Description
The Maldives Isolated Indian Ocean atolls with still lagoons surrounded by vibrant coral reefs.
Palau, Micronesia Hundreds of pristine tropical islands and Jellyfish Lake with minimal runoff or pollution.
The Red Sea, Egypt Calm, reef-sheltered waters with very little plankton growth and sedimentation.
Cocos Island, Costa Rica Remote Pacific island with stunning visibility, surrounded by deep waters and currents.
Galápagos Islands, Ecuador Cooler but very clear waters due to upwelling, low nutrients, and isolation from mainland.
Baa Atoll, Maldives Crystal clear lagoon protected by the Maldives’ deepest perimeter reef.
Ambergris Caye, Belize Clear waters due to offshore reefs and location upstream from heavy sediment outflows.
Abrolhos Marine Park, Brazil Vast coral reef systems filter and clarify surrounding tropical waters.
Raja Ampat, Indonesia Remote archipelago near heart of the Coral Triangle, isolated from pollution sources.
Fakarava, French Polynesia Pristine atoll with narrow pass to ocean, limited tidal flow maintains clarity.


For the clearest ocean water possible for swimming and snorkeling, remote coral reef locations in tropical areas are ideal. The Maldives stands out as one of the premier destinations in the world for crystal clear waters, white sand beaches, and accessibility. But many isolated islands and atolls throughout the tropics offer excellent water clarity and visibility for encountering marine life up close. Taking into account plankton levels, sediments, pollution, currents, and temperature allows finding the optimal conditions.