Belize is a fairly small country, and transportation between most destinations is rarely long and tedious.

By plane
Tropic Air and Maya Island Air both have multiple flights daily to various towns around the country and to Ambergris Caye and Caye Caulker. They fly out of both of Belize City's airports, but flights from Belize City Airport (IATA: TZA) are often significantly cheaper than those out of Phillip Goldson International (IATA: BZE). Domestic flights are generally pretty reasonable, and thus popular if your time is limited and budget is not. Most flights are in small Cessnas that seat around 8-15 people.

By bus
Several competing buslines operate on the main road in the north-south direction from Punta Gorda to Belmopan and Belize City. There are bus stations in the main towns, or simply stand on the side of the highway and wave at an approaching bus. Most buses have a conductor in addition to the driver, who stands by the door and will come to your seat to collect the fare at some point during the trip. Fares run anywhere from BZ$2-25 depending on distance traveled.
Express buses can save up to an hour and a half (depending on the distance of your trip); they do not stop for passengers waiting on the roadside, making only scheduled pick-ups and drop-offs in towns.
Most buses in Belize are retired US school buses[6] (Bluebirds), that have been given a slight makeover, a luggage rack installed, and sometimes a new paint job. They generally aren't too crowded, but you may have to stand occasionally.
Children selling snacks and soft drinks often board the buses at stops, and this is an inexpensive way to have a snack if you've exhausted what you've brought along or just want to try some home-made travel foods.

By Water Taxi
For those wanting a truly Belizean experience, take the water taxis from city to city. Generally it will cost you anywhere from BZ$2.00 to BZ$15.00 each way. Water taxis to Belize's two most popular islands, Caye Caulker and Ambergris Caye , leave from the foot of the Swing Bridge and from tourist village several times a day. These trips usually take about 45min, and 90 min respectively.

Car Hire
Of course, if you like to make our own itinerary when traveling around Belize, car hire is an option. There are several car hire companies based at the major airports for travelers convenience and some basic rules to remember are that the roads are bumpy - very bumpy - so a four wheel drive is the best choice. Lighting on minor roads is not great so stick to highways or day time driving. The main highways through Belize are the Northern Highway, beginning at the Mexican border, The Western Highway from Belize City to the border of Guatamala and the Hummingbird Highway which takes you to the Southern part of Belize. These will take you pretty much anywhere you need to be and are relatively well-maintaned roads.