Shuttle from MIA to/from Port

[sailandcruise]

I am traveling solo so a shuttle will be less expensive than a taxi. Do I need to make a reservation or can I just walk up to the shuttle at the airport? What about for the return -- can I catch a shuttle at the port without a reservation?

 

My flight arrives around 10 am on a Saturday and I depart MIA at noon on a Thursday.

[JohninDC]

American shuttel has the contract and an office inside the MIA airport; a reservation with them can't hurt. Good luck! :)