When you are snorkeling Molasses Reef you will not be alone. It is considered the most visited coral reef in the world. It was a top priority for us when we were in Key Largo. We heard that it was the highlight of the area, with it's large spur and groove coral reef in a nice variety of depths.
Because this reef is about six miles offshore of the Florida Keys, sitting on the edge of the barrier reef, conditions need to be fairly calm to snorkel it. And that is why we have not yet done it. The weather would not cooperate when we were there. But we have heard great things about the wonderful Elkhorn Coral, huge brain corals, abundant sea life, and clear waters. We found the following picture in the creative commons on flickr.
Obviously, you need to get on a boat for snorkeling Molasses Reef. You can get on a tour in Key Largo or at Pennekamp State Park. We are not sure if the large boats from the park or Key Largo go to Molasses as the companies often won't tell you the destination until you leave. But, you can book a private charter or a place on a boat with a max of six passengers, and you are more likely to be able to visit Molasses. Make sure you get on a snorkeler's tour, as divers go here a lot and they are diving deeper. Or, you could rent your own boat if you are skilled.
Along the length of Molasses Reef, boats can choose to tie up to 33 different mooring buoys. We understand that there is shallow enough depths for snorkeling at all but buoys 21-23. Also, the buoys that are nearest the lighthouse are shallower.
Because this is one of the further out reefs, you will find bigger species of fish and sea life in general. Expect to see turtles and rays; they are said to be common here. Goliath Grouper frequent the area. The visibility is also supposed to be excellent because it gets flushed by the ocean currents.
We became pretty familiar with this NOAA weather site when trying to decide if we should snorkel at Molasses. It is a weather station on the 45 foot light house right on Molasses Reef. And it is the best place to check out weather for the Key Largo area.
Here is a fun You Tube video of some folks snorkeling Molasses Reef. Looks pretty colorful and alive...