This vintage cotton gabardine swimsuit was made in the 1930s by Allen-A Life Guard. I’ve attached an ad from 1938 advertising this model. As opposed to the usual elastic or wool construction, these lace up at the hip. They have a round coin pocket. There is some wear and light fading, but these have made it through the past 70+ years remarkably well.
Marked size: 30
Waist minimum size (side to side): 14″ (doubled =28″)
Waist maximum size (side to side): 14-3/4″ (doubled = 29-1/2″)