If you can carry everyone's lunch to the beach in a backpack, that leaves everyone's hands hands free to tote the other essentials (paperback thrillers, sun block, coolers of icy drinks, floppy straw hats, etc.):
Above: A Market & Fruit Picking Pack, made of lightweight rattan, has a leather handle and cotton shoulder straps. It's $104 from Kaufmann Mercantile.
Above: The cotton straps are adjustable, allowing you to distribute the weight of the basket comfortably on your back.
Above: The hard sides will keep food from getting smashed of flattened; the bottom of the basket is reinforced with an ash wood runner. (N.B.: Looking for a place to picnic? See 468 images of Gardens in our Gallery of rooms and spaces.)