This summer, for once, hip is not what's happening—at least not on the beaches of America.

High-cut swimsuits are out and low-cut—on the thighs, that is—are in. And there's even a return to the kind of draped swimsuit that hasn't been seen since Esther Williams starred in Neptune's Daughter.

In fact, Williams, 65 and long retired as a movie naiad, has her own line of swimwear. "It just seemed to me that my knowledge of what feels good in the water should be put to work for the women of today," she said. "The group we are targeting is that wonderful baby boomer group of women who are now married and have had a baby or two and want to look beautiful. The swimsuits made for the older women were too constructed and too old looking, and the ones for the 18-year-olds were too brazen for yuppie women."

And so Williams, along with Norma Kamali and other designers, has gone back to the past. "Among our best-sellers," says Kal Ruttenstein of Bloomingdale's in New York, "are Kamalis that are inspired by, but not rehashes of, the 1940s."

One of Kamali's '40ish designs is the long-lined Marlene, named for Marlene Dietrich. It is black, with white collar and cuffs. "I think it's great," says Ruttenstein. "It's fun because the young women wearing them right now were not around for the '40s style. So it is a definite new look for them—great, sexy and very different on the beach."

Or, as Esther Williams says, "Since a swimsuit is the least amount of clothing that a woman will ever wear in public, I felt it ought to be cut right and built right. The real beauty of putting on a swimsuit and going into a pool or an ocean is to get wet as quickly as possible and enjoy that wonderful water, and then enjoy some sunning afterward."

And, as swimsuits cover more and more flesh, think of the savings in sun block.