Because the Cayman Islands are flat coral islands without rivers, there is very little natural runoff to silt the water, unlike the mountainous volcanic islands in other parts of the Caribbean. Visibility in Cayman's clear water can range from 60 -100 feet and year-round temperature averages 73 – 85 degrees.

The legendary clarity of the water around the Cayman Islands is primarily due to the lack of river runoff and the region's unique geography. Unlike larger landmasses like the United States or South America, the Cayman Islands are relatively small and do not have major river systems that dump silt, mud, and organic sediment into the ocean. This keeps the water exceptionally "clean" and free of the turbidity that often clouds coastal waters elsewhere. Additionally, the islands are surrounded by healthy coral reefs and a seafloor composed of fine white calcium carbonate sand, which acts like a giant natural mirror, reflecting sunlight back through the water and creating that iconic "electric" blue and turquoise tint. Because the water is relatively nutrient-poor, it also supports very little plankton and algae, which can often give seawater a greenish or murky appearance. The deep "Cayman Trench" nearby also helps circulate clear, deep-ocean water into the shallow coastal lagoons. This combination of Factors makes the Cayman Islands one of the premier destinations in the world for snorkeling and scuba diving, as the visibility can often exceed 100 feet.