Cruise lines need to occasionally move their ships from one home port to another. They do this to accommodate changes in seasonal cruising patterns. Rather than move an empty ship, the cruise lines book these passages as repositioning cruises. Repositioning cruises are often priced at a discount. One of the benefits for passengers is that the long one-way distances these cruises travel can offer a nice variety of things to see along the way (although some spend many days out to sea). The primary setback is that you’ll need to a return flight.
Here are some repositioning cruises that start in Miami: