Hyatt Regency Kauai Resort & Spa, Koloa, Kauai, Hawaii

Set on a beautiful but rough and rocky stretch of coastline, the hotel needed to go big to keep guests out of the ocean. The solution? A five-acre saltwater lagoon, which is totally enclosed, heated, filtered, and even equipped with a deluxe sandy bottom. Giving the feel of the ocean without the seaweed or current, the lagoon has kayaks to rent for exploring and several islands where guests can try out the relaxing hammocks. The resort also has a secluded, adult quiet pool with three 12-person hot tubs, and a larger action pool with waterfalls, a water slide, volleyball, hot tubs, and a roped-off area for small children. $375-$630; (800) 554-9288;
Whether you call them water features, fantasy complexes, or water parks, they have a lot of similarities. These are features you are likely to encounter as you shop for the perfect resort pool.

River pool: A narrow pool, usually just 5 to 10 feet wide, winding through rocks and vegetation to create a flowing, river-like experience

Zero-entry: A beachlike
entrance, with or without sand, where the pool's bottom slopes away gently, with no steps or drop-off, making it safer for monitoring children at play

Infinity pool: A pool, usually overlooking the ocean or another water body, in which the water level reaches the top of one edge and spills over to create the illusion that there is no wall but, rather, it goes on forever

Free-form pool: A pool with the irregular shape of lakes or ponds, rather than a conventional rectangular shape

Activity pool: A sports area, often with water basketball or volleyball nets set up

Cabanas/bungalows: A poolside home base, sometimes equipped with television, bathroom, and room service, that you can rent in addition to your regular room