We just finished the drive to Panama a couple of weeks ago. We have been fishing the whole way with no license, some countries do require a license and fishing is illegal in most National Parks (you would not know it when you're there due to the dozens of locals fishing).

I really wish I had my Hawaiian sling. I have met other folks traveling with slings, not spearguns. Slings can look like simple poles when the spear tip are safely stored elsewhere in the vehicle, while spearguns look a lot more like weapons, are expensive and can easily be confiscated by customs or cops along the way... just my honest opinion and .02 cents.