The best keys snorkeling in Florida is actually not where most people think (it surprised us). While Key Largo and Key West are the most popular spots, by far the best snorkeling is to be found between these two keys.
There are a bunch of snorkel locations that are simply stunning, some of the best we have ever seen anywhere. They are located in the waters off Islamorada (Matecumbe Key), Marathon (Vaca Key), and Big Pine Key.
We call all of these lesser known snorkeling grounds the Middle Keys, because, well, they are in the middle.
All of these reefs are reached by boat tours, and we normally prefer destinations that have more beach access. But we don't let that stop us, because the health of the reefs at these locations make the Florida Keys one of the best places to snorkel.
We will go into detail below about each of the Middle Keys snorkel spots below. You can also explore our main page for snorkeling the Florida Keys.
Islamorada is actually on Upper Matecumbe Key. But everyone seems to refer to the area as Islamorada because of the town. We drove down to snorkel these spots from Key Largo.
There are several wonderful little patch reefs that are about halfway between the key and the outer barrier reef edge.
This is a perfect snorkeling location. The depths are fantastic and the area is packed with medium sized fish and wonderful corals.
This is another patch reef area that was wonderful. This site is remarkable for all of it's healthy hard corals and sponges and interesting underwater topography.
Farther out in bluer water is the amazing Alligator Reef Lighthouse. This is a great snorkeling spot. There is a tall lighthouse structure, and thousands upon thousands of fish congregate underneath it for all the shade it offers. It is a fairly shallow area that is a joy to explore.
There is also a second area that you should snorkel while at the lighthouse. It is a deeper canyon wall just east of the lighthouse. Very deep but full of big creatures!
Marathon is actually on Vaca Key (Cow Key?). And there are several really nice inner patch reefs available to snorkel from Marathon, as well as an amazing barrier reef snorkel.
From Marathon you can get a boat ride out to snorkel the Coffins Patch area. We snorkeled two different spots in the Coffins Patch, and both were good. These locations are often combined in one boat trip.
The first was The Donut. This is a better diving than snorkeling spot because it is a little deep. But we still really enjoyed it for it's amazing profusion of sponges.
The second spot is called The Stake. This is a much better snorkeling spot, because it is less deep.
You can't miss this, it may be the best Keys snorkeling spot. This wonderful spur-and-groove reef is full of interesting topography to explore and many fish and corals to see.
Just south of Marathon is this fantastic park with mediocre beach snorkeling that is worth it nonetheless.
Pretty much the snorkeling that everyone does from the Big Pine Key area is the amazing Looe Key Reef.
Looe Key Reef is yet another not-to-be missed Florida Keys snorkeling spot. But this spot is not for the faint of heart. It is a bit deep, and is right on the edge of the barrier reef. The fresh flows of ocean water attract large creatures here, which is why divers love the area. Giant Groupers and sharks are not uncommon sights here.
There are other good snorkel spots around the Middle Keys, but this should get you started. Once you decide on a location above you can read some TripAdvisor reviews about what boat company to use.