Taking the Intercity Public Bus

Belize actually has a great public bus system for moving around the country. If you ever wondered where old school buses from the US go to die, well now you know. The bus ride is is a great thing to experience; riding along in a big school bus with the windows open and reggae playing on the stereo. Its not the smoothest ride (especially on the dirt road heading south to Punta Gorda), but its a great way to mingle with the locals. The fares are very reasonable and most of the time there are a lot of open seats. The buses are operated by several transport companies so for most locations there is a bus leaving every 30 minutes to an hour. You can ride west to Guatemala and cross at Benque Viejo del Carmen and ride north to Chetumal, Mexico and south as far as Punta Gorda.

National Transport is one of the bigger bus operators and you can find their schedule here http://www.nationaltransportbelize.com/schedule/

This site has a pretty good description of the bus setup in Belize as well
http://belize-guide.info/getting.around/buses/