Key West. Those two words often bring about images of parties on Duval Street, incredible restaurants serving fresh seafood, and, of course, stunning beaches. The white sand that gives way to perfectly clear blue waters is the stuff that island dreams are made of.

Key West is famous for its clear, turquoise waters, but it differs from many other Florida destinations because it is built on a natural base of coral reef and limestone. This unique geography provides excellent underwater visibility—often reaching 50 to 100 feet at the offshore reefs—making it a world-class destination for snorkeling and diving. However, this same limestone base means that Key West has very few natural "sandy" beaches compared to the Gulf Coast. Many of the island's most popular beaches, like Fort Zachary Taylor or Higgs Beach, have water that stays clear year-round due to the gentle tides and protected shallows. For the absolute clearest water, many visitors take a day trip to Dry Tortugas National Park, located 70 miles west of the island, where the untouched coral reefs and open-ocean currents provide a "Caribbean-blue" clarity that is nearly unrivaled in the United States. While the water at the shore can sometimes appear murky after a heavy storm stirs up the sediment, the general environment remains one of the clearest marine habitats in the Atlantic.