When we were on the western a few weeks ago, we did 2 snorkel excursions which were very different, but we enjoyed them both.
Key West- Fury Sail and Snorkel (booked through Disney)
This was a pretty long trip in the hot sun. We left around 1 pm. It took an hour to get to the reef, we snorkeled for about an hour, then an hour back. The water was approx. 15 feet deep. While we were on this excursion, the water seemed calm, but compared to the second excursion, this water was had a few little swells. Remember-they were just small swells, but noticeable, especially when comparing the 2 trips!! The visibility was good as we saw some fish and DS and I swam over a shark twice about the size of my 14 year old. It didn't bother us at all, but just something to keep in mind if your child has a fear. Snorkeling equipment was provided with a floataion vest included. This vest does keep it very easy to stay a float and they are required. (you don't have to fill them up, but you must wear them.) The crew was great, but they were pretty strict about procedures, etc.) Free soda, water, and beer on the way back.
Grand Cayman-half day snorkel trip (booked ourselves through Captain Marvins)
This is a private company and the tour lasted from about 10am-1am. I think we even set out a little early because everyone was there. Only about 25 people were on this boat. We had three stops. The first 2 were spots along the reef in water about 9 feet deep. The equipment was in great shape and I feel a bit nicer than what was provided in Key West. Floatation vests were provided, but we did not have to wear them. Actually, our stuff looked brand new!! It seemed to fit me much better also. The water here was very, very calm and crystal clear!! The crew seemed to interact more with us (but it was also a smaller group and boat). They would show us things under water. One crew member led a moray eel out from it's hiding spot a bunch of times to allow us to see it. Snorkeling here was like being in an aquarium-words can't describe the beauty!! The third stop was Stingray City which is about 4 feet deep, but the stingrays can be intimidating. (very, very safe though!!!!) They also had a diver taking videos that he made into a video or DVD you can buy.
Please understand that the Fury Catamaran was great and I am SO glad we did it also, but if we had to choose, Captain Marvin's would win hands down.
Don't forget, you can snorkel at
Castaway Cay which is very calm and staggered with lifeguards.
Have a wonderful trip and PM me if you need more info!
Karen