Belize City
Belize City was 2, Caye Caulker was 22, Ladyville was 25, San Pedro was 26, Burrell Boom was 28, and other outlying areas around Belize City were 21. Presumably, no Belize City number would begin with 1, 2, 5, 6 or 8 in order to avoid confusion in the switch (e.g. 28-8012 could be mistaken as 2-88012).