The Atlantis Resort is HUGE! Prepare to do a LOT of walking. I'm positive that it's bigger than Disneyland! There are many, many pools to use. There are smaller ones by the Beach Tower, including a kids' play area, lazy river ride and small water slide.
The water on the slides here was quite cold, so we only did them once. We heard that the water in the lazy river was cold, too, so we didn't even try it.
Near the Coral Towers, there is a large freeform pool. Between Coral Towers and the Royal Towers there is a large lagoon, where you can swim, snorkel, ride kayaks or paddle boats. We didn't even check those out, so I don't know about fees. There is a sandy beach on 2 sides where you can relax and watch the activities.
Near the Royal Towers is where all the excitement is. There you'll find another large pool, another kids' pool and the Mayan Temple and slides. The body slide is very exciting. You climb to the top of the temple, then plunge down the slide and through a clear tube through the center of the shark pool. You're going fast, and water is spraying in your eyes, so you can't see anything through the tube, but it's still a thrill! At the end of the tube you are dumped into a small pool where a lifeguard hurries you out to make way for the next rider.
At the opposite side of the temple at the very top is a pair of slides where you can race with a friend to the bottom. That slide is not as steep, but it goes very fast. So much water was spraying in my face, I couldn't see whether my son or I was the first to reach the bottom.
My favorite was the tube slide. It's one level down from the body slide. You ride an innertube through a large tube that sends you snaking down. It goes pretty fast and it's very dark. At the bottom, you are dumped into a clear acrylic tube in the middle of the shark tank. Here you mosey along, pushed only by the force of the water in front of the person coming down the slide behind you. You can enjoy the sharks as they swim beside and above you as you float by. People outside the tank can also see you through a large viewing window. These slides have a 48" height limit. There is one slide for smaller children. I didn't see a height requirement on that slide.
For all the water attractions, including the beach at Atlantis, you must have a wristband. You can go to any towel stand (aka Liquid Adventures Center), show your room keycard, and receive a towel and a wristband. If you choose not to wear a wristband, keep your card handy because you'll be asked to show it a number of times.