Phuket is a world renown destination for scuba diving aficionados. The main scuba diving sites in the area are Shark Point, Racha Yai, Phi Phi islands, Anemone Reef and Yai Island, which can be visited on a day tour
If you have two or more days and you are into scuba diving, you should not miss Similan Islands, one of the world's top ten diving destinations. Most diving schools in Phuket offer Liveaboards to the Similan Islands. A stay of, at least, two nights on the boat is recommended.
If you click on the picture, you will see a video of a Leopard Shark I shot in the Similan Islands.