The port of Miami parking is notoriously bad. There are so many people who go in and out of that port, that they all need to leave their cars somewhere. Though finding a place can be difficult, you just need to look a little ways out. For example, I would recommend looking within a few miles of the port, rather than simply right next door. Your best bet after that is to take the shuttle. Shuttles around that area offer the best way to get to the port without having to park your car in a very obscured spot. Though you can get lucky from time to time, it’s best not to risk it.