The 8,000-square-foot, freeform swimming pool at Four Seasons Las Vegas has two whirlpools. Guests in the sun can be spritzed by Evian-bearing attendants. There are also shady arbor spots.
Didn't bring a swimsuit? Ask for one of the disposable ones the hotel can provide. Those in the mood for the beach can access the sand-and-surf one at Mandalay Bay, next door.