Right after the famous view point on the way from Karon / Kata beach you will find a small road leading into the forest and down to this well hidden beach. Here you also find a restaurant and bar where you can rent various water sport articles. If you don't feel like driving the road down to the beach you can always enter this beach is by sea, just ask a long tail boat to take you there and then pick you up again in the afternoon.
There are several coral islands to the south of Phuket, the Similan Islands lie to the north west, and Phi Phi Islands to the south east.