Spearfishing in Thailand is not illegal
THATS TRUE !!!
I am spearfishing in Thailand for more then 15 Years and I never had problems with any authorithies.
There are still many places, which are no marine-parks, but Scuba-diving
growth up that much the last years, that its better to have a Thai with you,
if you don't won't get override by a dive-boat.
Very often are more then 30 divers :duh on one boat, and when this herds of divers are released in the water, beware of the boat-driver !!
It hapened more then once, they let there dive-boat float to the place where we are, pushing us away or starting their engines near by us, to get washed away.
Meanwhile, mostly seen at japanese divers, this herds of divers destroying a lot off corals,,, they don't now to weight-balance cause off lack of solid education. (Palm-tree-brevets)
Better not to start much discussion with these thai boat-owners if you alone,
because in Thailand guns are wide spread and they think, they have to protect their source of income (even if not a marine park)
greetz