I have to admit that I was scared to death to do this, but it turned out to be my favorite thing that we did. The thought of getting in deep water at night terrified me, but it wasn't bad at all. The boat takes you to a spot near a hotel that has blue lights that attract the plankton the mantas eat. You get into the water and swim to a platform with handles all around. You can see the bottom of the ocean, maybe 20 feet down? But the fact I could see the bottom helped me relax. You hold onto the handles and look down. The mantas will swim right up from the bottom towards you with their big mouths open scooping up the food, and then right when they get to you/the surface, they turn and go back down. It's awesome, and the guides were awesome and informative, too. Loved it!