They say that everything that was once in fashion comes back again, and this season's hottest designer swimwear collections are proof of that. Retro bikinis are all the rage for women who want feminine, flattering two piece swimsuits for the beach or pool. To help you bring the retro bikinis look to your swimwear wardrobe, here are three of the biggest vintage trends currently in style:

1. Vintage Silhouettes - Many of the most fashionable retro bikinis are drawing inspiration from 1950s swimsuit designs. Similar to the two piece bathing suits worn by Bettie Page and other '50s pinup swimsuit models, these retro bikinis are proof that bathing suits don't have to bare it all to be sexy. Flattering for straight and plus-sized women alike, silhouettes of retro bikinis offer fuller coverage with higher waists that travel to or above the navel. The designs of these retro bikinis often include halter tops with underwire that support and lift the bust.

2. Throwback Patterns - If you prefer a traditional low-slung bikini bottom but still want the style of retro bikinis, choosing a suit with a throwback pattern is the perfect way to get the look. Vintage patterns on retro bikinis include '60s-inspired floral prints, tie-dye patterns, polka dots, gingham-style stripes and wild '70s-inspired geometric prints. You can find retro bikinis with all-over patterns and looks that pair a solid top or bottom with a print on the other piece.

3. Flirty Finishes - Many retro bikinis have fun finishing touches that add to their style and their vintage appeal. This season, designers are showing retro bikinis with fringe along the neckline inspired by 1970s fashions. Ruffled bathing suits reminiscent of the 1940s and '50s are being shown in many designer collections, and you can also find bikinis with sequins inspired by the fashions of the 1980s.