I live in Southeast Florida. The distance between the two airlports per se is probably around thirty miles...BUT.....Miami traffic is the worse traffic in the world. On a good day.....the travel time between the two airports can be had within a half hour....BUT......at other times it could take well over two hours. There is no rhyme or reason with Miami traffic. Mid morning can be herrendous. (sp) I personally have totally stopped using MIA to SXM. FLL is so much easier, and usually with Jet Blue...MUCH cheaper than American Airlines. The only reason i can think of why you want to fly to SXM from MIA would be you are using frequent flyer miles?? Even though it wasn't mentioned yet.....the return flight is a slam dunk easier and quicker through FLL...than MIA. Last few times coming back through FLL we were through the entire process within fifteen to twenty minutes.....vs the HOUR PLUS, and also the LONG WALK through MIA. If you decide to do the FLL then MIA route...make sure you give yourslef at least a four hour or more window. Good luck with the decision.