The cheapest and most popular way to go out is on a large party boat. Several companies offer this type of excursion and it is usually the least expensive. You go on a large catamaran boat with as many as a hundred other people. Now this can be good or bad, if you want peace and quiet probably not so good.If you are single and on vacation maybe meeting numerous other single people on a boat in your bathing suit is actually great.

Most tour boats in general provide snorkeling gear and in cooler month will do wetsuit rentals. Now the water in the keys are warm but in the winter if you are in the water for awhile they will not seem so warm. So if you plan on spending every moment you can in the water you will want a wetsuit in the winter.

Now one suggestion you might want to look into is buying your own mask and snorkel. They are relatively small and can be packed easily and frankly having a comfortable well fitting mask can make a huge difference in your experience in the water. Also there are nice “dry snorkels’ which can be purchased that block and spray from waves which might enter the snorkel . There snorkels are not all that expensive and can add a lot to your experience.

Common snorkel spots for the large boats to go to are Sand Key, Rock Key, Eastern Dry Rocks and Western Sambos. They are all pretty good snorkeling destinations and are on the outer edge of the reef  where the water is consistently clearer then more inshore.

Another option when going snorkeling is taking a private or small boat. This gives the advantages of going where you want, staying in the water longer , hitting more spots, in general a better experience. Of course the downside would be price.  There a lot of areas on the reef where there is much more live coral and fish then the main snorkeling spots so keep that in mind when choosing your trip