I have not done this, but when we were at Coral World, we went to the semi-submerged aquarium and were able to watch the trekkies for part of their trip. It looked like they were tethered to a line as they walked through the water. I could see that they did not go out very far, but I couldn't tell whether they were able to see sharks or other "interesting" creatures. It looked sort of fun to me, but I probably would not pay $195 for it. Good luck and have fun with whatever you choose to do.