White rock is about one kilometer south of Koh Nang Yuan. It's about halfway between the docks at Mae Haad on Koh Tao and Koh Nang Yuan. Although it's in open water, this is a great dive site, suitable for all ranges of divers.
The rock is a granite boulder that extends up to just a meter or so below the surface. There's a second large boulder not far away, and many smaller rocks along the bottom. The variety of fish here is often quite amazing. In a single dive you'll likely run across several pairs of Moorish idols, blue ringed angelfish, and even a moray eel or two.