If you want to dive the fabled local waters without getting wet (or certified, for that matter), board the Atlantis submarine. Though you’ll descend to 30 meters (100 feet), your ears will be none the wiser, thanks to the sea-level pressure inside the vessel. And without the continuous need to equalize that usually accompanies such depths, you can focus exclusively on the amazingness around you: barrel sponges, star corals, huge numbers of tropical fish and the occasional ray or turtle.
Go on a wreck dive without having to suit up when you join a semisubmersible submarine excursion. (Unlike a true submarine, this doesn't descend completely below the water though the passenger cabin has large windows that take in the scene below the sea.) Board the Seaworld and you'll sit 1.5 meters (five feet) below the water’s surface as you visit the sunken remains of the Cali, a 1900 schooner, and the Balboa, a 114-meter (375-foot) freighter. In between, you’ll visit Cheeseburger Reef, essentially an open-water aquarium where divers feed massive schools of Technicolor fish.