It is per cab and not per person. Make sure that you confirm that before you get in the taxi anyway. I don't remember hearing of any taxi driver in Coz ever trying to rip off a tourist but there is always a first time I supposed.
And don't forget to confirm that price when taking the taxi back to the ship. We had no problems............have a great time at Chankanaab!!! Be sure to play mini golf there--just a couple of bucks extra. It's a small course. The day we were there, a big iguana decided to sun himself on the course. Made for an interesting game.