Phoenix Divers is the most excellent for scuba dive and freedive on Lanta. Superior boat, high quality equipment and unbeatable breakfast and lunch. I was diving with them for 4 days and every time we went to a different place. They are also Green Award center and you can see that everywhere, from their food preparation to how they handle their boat.
I definitely recommend Phoenix Divers for your scuba and freedive adventure on Lanta!