A button front beach cover up dress gives you easy on and off without pulling over your head which matters when you are wet. The buttons should be plastic or wood not metal which rusts with salt water. The dress should be loose and comfortable to wear over a swimsuit. Knee length or longer is the right proportion for a cover up. The fabric needs to be lightweight and quick-drying. Button fronts are practical and they give you the option to wear the dress open over your swimsuit or closed for more coverage. Pair with simple shoes or sandals. These dresses work because they solve the actual problem of how to get from the beach to lunch without changing.