Similan Island water is truly as blue as it is in this picture, no doubt a gorgeous part of the world. Well organised, wonderful attentive staff. Really enjoyed the first Island, second Island where we had lunch was just so overcrowded that you literally had to walk over people on the beach, I mean step over them. To get any sort of swim you needed to go pretty far out from the beach because in the water you were always bumping into people. Its a national park and it was disheartening to see it being abused in such a manner, literally having thousands on the beach at the same time is doing so much damage. The reason I gave this a 4 was because Ill remember the colour of that water forever and also the staff. I would of liked to have seen fewer people on the boat, it was very crowded.