Not All Swimsuits Are Equal : Shopping: Before you buy, consider your plans and your need for stylish fashion versus smart function.

Swimsuits, like shoes, come in several types--stylish or sensible, pretty or practical.

So before you buy, inventory your needs for fashion versus function. Does your idea of the perfect beach day include nothing more challenging than poolside lounging? At some hangouts in Newport Beach or Palm Beach, the water is merely incidental to the real action--seeing and being seen.

Then again, you might be into serious swimming, and your flashiest accessory is a pair of fins or swim goggles.

“There are hundreds of swimsuit companies, and basically you’re looking at suits that are water-efficient versus those meant for lounging at the beach in Hawaii,” says Lois Fahey, owner of Swim ‘N Things, a Denver swimwear store. “So we try to ask customers if they’re looking for something to be active in or a fashion statement. Your usage of the suit will dictate what’s best for you.”

First, think fabrics.

At Speedo Athletic stores, the key fabrication for active women bent on aquatic speed is nylon-Lycra. That combo offers the least resistance and isn’t quite as heavy as cotton, which soaks up more water, according to a Speedo spokesman.

On the fashion front, this season’s trendiest swimwear is cut from materials typically used for ready-to-wear, such as crushed velvet, metallics and crochet. Elegant enough to sail straight from pool to cocktail party.

The good news is, velvet swimsuits are more durable than you might think, says Michelle Boylan.

“People have a misconception of what velvet swimsuits really are. They’re actually made of nylon and Lycra,” says Boylan, vice president of Beach Patrol, a swimwear manufacturer based in Carson.

“The velvet is a product of a brushed finishing process of the nylon-Lycra. True velvet would have cotton or silk, so it’s actually faux velvet.”

Beach Patrol offers velvet maillots and bikinis in black, forest green, burgundy and plaids, accented with gold-tone details. They sell for about $60 at department stores.

“They’re made for a poolside party atmosphere, and they can go out at night if you add a chiffon flared skirt or a pair of jeans,” Boylan says. “We see our swimsuits as bodysuits functioning as day-to-nightwear.”

Or dress up in a metallic swimsuit. For trend worshipers, precious metals continue to shine bright in gold, silver, bronze and pewter--even though some metallics work double time as conductors that reflect the sun.

Nonetheless, metallic suits are your ticket to the cutting edge of poolside perfection.

“Silver is the most important and versatile color,” Boylan says. “Just add silver lace-up strappy pumps or ankle-tie pumps and a chiffon sarong.” Plus Hollywood shades, bold bangles and turban for that glamour girl look.

If you’re bent on looking like a million-dollar mermaid, try a suit that recalls the glitz of bygone Hollywood days. Among the retro styles are suits with high-banded waists and teeny skirts. “Very flirty and fun,” Boylan says.

But not the most water-worthy, according to Fahey of Swim ‘N Things.

“Buying a skirted swimsuit is the most common mistake if you’re going to be active in the water, because the water bubbles under it and the skirt gets in your way,” Fahey says.

“If you’re looking for a water-efficient suit, skip the ruffles, the gathers, the skirt. You just want something as sleek as possible for the least amount of drag in the water.”

If tracking down a wearer-friendly suit is your goal, a one-piece suit scores for athletic appeal.

At Speedo Athletic stores, the one-piece S-2000 is one of the most popular high-performance suits. With high neck and high-cut shoulder and leg styling, the body-hugging style prevents drag due to water seepage. About $65 to $79, depending on color and print.

Or try a “workout bikini,” Fahey says.

Tyr offers a workout-worthy nylon-Lycra bikini with athletic sports-bra top with T-back straps, plus high drawstring bottom. The line runs about $50 to $65, in reversible solids and prints.

“The main thing is they hug the body real well and are very secure for activity,” Fahey says. “So you won’t lose your bathing suit no matter what you’re doing.”