Swimsuits from the 1950s were incredible. Continuing the trend established in the early 20th century, more skin was displayed near the water than ever before.
These swimsuits followed the popular silhouette of the day and the fashionable shape of the body as seen above — an hourglass shape.* They mimicked undergarments from the time (like bras, waist cinches, and girdles), molding the body with bra cups, boning, control panels, and stretch fabric.
Because these bathing suits had a foundation of their own, they could be worn with or without straps.
The cut of the suit was straight across the top of the thigh creating a modesty apron. That modesty apron hid the fabric that covered the privates. Some suits had bottoms shaped liked shorts, skirts, and/or bloomers.
Two-piece suits were worn mostly by actresses or other celebrities. Few common women in the United States were willing to wear something so risqué in the 1950s.
The most common fabrics used in bathing suits were cotton, nylon, and Lastex, which is a trademarked name “used for an elastic yarn consisting of a core of latex thread wound with threads of cotton, rayon, nylon, or silk and used to give a one-way or two-way stretch to fabrics and garments.”
As a personal preference I wish I could find bathing suits just like the ones from the 1950s. I know that there are contemporary labels that make vintage-style 1950s suits, but they aren’t quite the same. The cut of the leg of the reproduction suits would have been considered high back then. I’ve never seen a recreation that incorporates boning or other foundational shaping used back then. Unfortunately everything relies solely on stretch fabrics today.
*The desired hourglass shape was created by restrictive undergarments that hadn’t been worn since before the 1920s.