"Adults getting hepatitis B vaccine require 3 doses — with the second dose given 4 weeks after the first and the third dose 5 months after the second."
"HEP A - For travelers, it is best to start the vaccine series at least one month before traveling. (Some protection may still result if the vaccine is given on or closer to the travel date.) Two doses of the vaccine are needed for lasting protection. These doses should be given at least 6 months apart.
Some people who cannot get the vaccine before traveling, or for whom the vaccine might not be effective, can get a shot called immune globulin (IG). IG gives immediate, temporary protection."
Note: Immune globulin or Gamma Globulin is unlikely to be avaliable on the island...and I would start these in the States to gain the partial immunity as the likelyhood of these being readily availble in Belize is a good question