Give the mismatched bikini from your 20s a fashionable upgrade with a more sophisticated suit. Use the halter straps for extra support and the on-trend bustier style.

Shop it: Zimmermann Sundown Bikini, $230

Mask any stretch marks or scars with a sexy cutout one-piece that still shows some skin and still looks like a bikini from the back.

Shop it: Vitamin A Brena One Piece, $185

A crisp, all-white bikini makes a statement, whether you're at a P. Diddy party or not.

Shop it: Akras White Eloisa Bandeau, $240

Dunn says this decade is a "swimsuit free-for-all." By this age, women are more comfortable in their own skin, so it all depends on how you feel. "A woman might wear an itsy bitsy bikini she's had since her 20s, and look just as great now as she did then, or sport a covered up look at the pool or beach and look equally as stunning," says Dunn.

Look For: Quality, well-made suits, flattering necklines and skirted bottoms if you're worried about problem areas.

Consider this chic one-piece your LBD in poolside form. With sexy peeks of skin and supportive underwire cups, this suit is guaranteed to turn heads.

Shop it: Agent Provocateur Marnee Belted Swimsuit, $790