1- Bimini Islands, Bahamas
2- Culebra, Puerto Rico
3- Salt Cay, Turks and Caicos
4- St. John, U.S. Virgin Islands
5- Makaha Beach Park, Oahu
6- Bunaken National Marine Park, Indonesia
7- Rurutu, French Polynesia
8- Great Barrier Reef, Australia
9- Fiji
10- Florida Spring Holes
According to Forbes.com