There are no buses from Philip S. W. Goldson International Airport (PGIA). A taxi to Belize City costs BZ$50.00, and takes just under 30 minutes. Before exiting the airport, try to find another person to share a taxi and split the cost.
Another option is to walk or taxi from the airport to the Northern highway (about 2.5 km) and wait for a bus. As you approach the intersection with the highway, Belize City will be to your right so just wait on the side of the highway. When you see a bus coming, wave your arm up and down to get it to stop; Express buses will not stop. If you’re going to Belize City, the bus will terminate at the bus terminal. You then have to taxi or walk to the water taxi terminal.
Gasoline prices have just been increased to about BZ$9.00 per gallon -- don't be surprised if there's an increase in the taxi fare.
ATMs have accepted my card which was not issued in Belize.