Welcome aboard SB
First of all I don‘t surf, I’m the friend on the beach taking the great shots.
I’m assuming you really want to take your board and getting one at your destination is out of the question.
So as far as suggestions-
Get a good bag/used box from surf shop, if the fin(s) detach do it, and make sure there’s plenty of cushion.
As an alterative you might also check with FedEx (employee discount on shipping.)
Hopefully someone that has actually shipped a board will comment.