I have done the aqua seas tour in 03, 08, and 13. We have done a few tours, including dolphins X3, undiscovered future world, Segway x2, keys to the kingdom, backstage magic, wild Africa trek, etc etc.this is my second favorite tour. (Backstage magic is #1)
I have never done it anywhere else. You are not snorkeling. You have a rebreather tank, and and float vest with a wet suit. IF you have no experience with using a rebreather it might be hard for a second or two to convince yourself to breathe in without a snorkeling tube....but once you do, it is easy and awesome. There are two scuba divers in the water with you...and when he saw I was struggling for a second, he was right at my side.
The water felt cool cold but the wetsuit does its job keepin you comfortable. There are lots of animals, including sharks and turtles, that are very curious and will swim up to you. I had an amazing experience with a sea turtle who swam right up to my nose, practically, and then swam away. You are instructed not to touch, and especially the turtles, who are endangered....but they might touch you! ( never happened to me but my hubby got lightly tapped in the arm by a curious turtle.)
I thoroughly enjoyed the experience and loved doing it each trip. People can see you who are walking around the living seas and will wave you over, which was really cool. It was very relaxing and some of the time I would lay flat out and just float, watching the animals far below.
The tank is very deep, so you can not walk or even come half way down the tank. We got the tour as part of the platnum plan ( all tours and food, including room service, included.) my hubby did not like it as much as me because he is horribly nearsited and could not wear his style of glasses under the mask. He saw stuff, but only up close. I loved it so much I did it on my own without him, Twice!