I go several times a year to Jomtien to bring my child for diving.
Jomtien is near to where I live and the diving instructors are pretty good.

Yesterday, while chatting with a few friends (from which several are frequent divers too),  someone told me that there would be a very good diving place in Sa Kiaw at the Navy base.
According to him, citizens were allowed to go dive there too.
But he could not give more information about fees, equipment, and so on.

I would gladly hear if TV members know this place and can provide some more information.

TIA

I think you'll have to find another way to get more information. Nobody is active on this website, and I am really not familiar with that area.