[ruck'n'reefer]

It would be well worth it to go to the perentian islands in malaysia (if you are in the south of thailand). Only a couple of hours southest.
The best snorkeling i have done. I liked Koh Lanta, as well as the Krabi area. There are a couple islands in the southwest that you could check out.
Koh Toa is good for diving though.

BTW YOur email link doesn't work.