The 48 passenger Atlantis Submarine is an advanced technological marvel. Discover the vast coral canyons and brilliant tropical fish of Cayman's National Marine Park to depths of 100 feet. The SeaWorld Semi-Submarine is an incredible floating observatory. A few steps inside, you're in a wall-to-wall glass-viewing chamber gazing at teeming shallow reefs and shipwrecks. Atlantis also offers kayak, catamaran sailing, jet boat, snorkel and trolley train tours.