Concierge.com's insider take:
Once Vegas hotel owners realized that the nightclub set was either sleeping the day away or trying to wave down a cocktail waitress by the pool, they hit upon a business opportunity: the poolside club. So began Rehab, a daytime, poolside party at the Hard Rock Hotel that debuted in 2004. On Sunday afternoons, the hip and sexy spend the day soaking up sunshine, eating and drinking, and flirting with one anotherall accompanied by a live deejay or hip-hop act. That scene still thrives, but today there are options almost every day of the week, and most of them allow for European (topless) sunbathing. Moorea Beach Club is separated by a wall from the massive beach complex at Mandalay Bay, with its third-story cabanas, beachside gaming, and sea of chaises. Moorea is the intimate meet-and-mingle option, where the crowd is mixed and the vibe laid-back. Bare at the Mirage feels like your rich Miami friend's backyardit's small by Vegas standards, but dark planks of wood and overgrown trees make it feel secluded. There's an aboveground, glass-walled pool in the VIP area and tiered cabanas where topless sunbathers show off their, um, goods. Tao Beach at the Venetian is a mirror image of the eponymous nightclubloud, fast-paced, and geared towards younger spring-break types. MGM's new Wet Republic is one of the largest European-style pools, and Venus at Caesars is favored by those looking for a more relaxed scenethough it's run by the folks at Pure nightclub, so expect things to heat up eventually.
These special pool areas are sometimes only open on weekends, so call ahead or check web sites. And always be among the first to arrive, or reserve a day bed or cabana, lest you find yourself sitting along the pool's edge or—worse—nowhere at all. Cabanas can set you back over $1,000, so call for pricing.