From one sun-fearing, swimsuit-hating beach glass collector to another: I just wear a sundress and a sun hoodie. In fact, I wear a sundress to swim in, too, even to pools and rivers and lakes. I don't even own a swimsuit. Screw swimsuits. They're expensive and they look bad. They're stupid. Our foremothers swam in skirts and so can we if we so choose! (and modern options for fabric are much lighter than the wool and cotton of yesteryear- you'll hardly know it's there and you'll look epic!)
Also, for ultimate seaglass finds, head to Asia. A lot of beaches were used as landfills for years and years, and now, 30-50 years after that ended, they're filled with the BEST treasures. Old army buttons, marbles, and more glass than rocks or shells. Just go to a less populated area and ask an older local which beach used to be the trash bin. One of my biggest sorrows on leaving Asia was having to leave like 90% of my seaglass there. It's heavy stuff, expensive to ship, so I only brought the best stuff back.