Glass-bottom boat to Molasses Reef

Molasses Reef lies about six and a half miles off Key Largo at the outer edge of the reef line, in roughly 10 to 30 feet of water, deeper and farther out than the reefs the snorkel boats use. The glass-bottom boat from John Pennekamp Coral Reef State Park, the 65-foot catamaran Spirit of Pennekamp, takes up to 130 people and makes the round trip in two and a half hours, taking in a number of shallow reefs.

The reef carries scars. In 1984 a 122-metre freighter ran aground here and wiped out thousands of square metres of living coral; reef modules and coral transplants went in afterwards. You stay dry the whole time, so it suits small children and non-swimmers, and the boat takes wheelchairs (though its restroom is not adapted). It can roll in a chop; seasickness tablets are sold in the park gift shop. Booking ahead is advised, and you confirm in person at least an hour before departure. The park charges its own entry fee per vehicle on top of the tour.