A high waisted bikini and sunglasses for while the sun shines. Shorts and a t-shirt for sitting in the shade once you've had enough sun. Sandals and an oversized shirt for later around the fire when the sun goes down. And a large tote to put all the extras in. Don't forget the sunscreen.
Denim shorts will go with anything! So I based this whole thing on the bathing suit colors: white, black and aqua.