This terrific Catalina swimsuit with it's Pucci inspired fabric design is a 1960's or early 1970's example of the one-piece maillot showing strong fashion influences.
It has many details that I will show here, so you can really see how these bathing suits were made.
In the photo above, the body shaping is apparent. This suit has a built in bra, along with a back zipper and attached lining in the bottoms. The fabric is a nylon tricot that has limited stretch 'side to side' and no stretch 'up and down', so it cannot be stepped into, and must have a back zipper. There is a narrow belt around the waistline and ball buttons at the neckline.
The briefs have 'boy leg' style, with a very short 'leg' that has princess seamlines in the back to create a smooth fit.
The back view shows how the zipper fits from the scoop neckline down to the hip level. The princess seamlines are also seen here in the briefs.
The straps don't stretch, but they do have buttons to change the length. Inside the 'hard cup' bra is sewn to the lining of the neckline. The neckline is faced with a stretch mesh, and the bra cups are sewn to that as shown below.
The picture above shows the narrow belt with clear ball buttons like the ones at the neckline.
The lining for the bottoms is white tricot, sewn into the waistline. It has elastic at the legs to keep this panty in place.
Designed and made in California, Catalina swimwear was a staple in the regional design community, known for quality and fashion styles.
This swimsuit is listed for sale in my shop, PintuckStyle on Etsy. The measurements for it are included with the listing if you are interested in that information.