Last time I went to AC, I used my Discover Card to book my airline tickets and they sent me a letter that said if I used my Discover in Belize, there would be no transaction fees. Not that many places take Discover. That said, I just brought some US cash down (agree with PP, no ink stains, tears, or major wrinkles in your US cash. Weird rules imposed by local bank two days before my arrival) I never used a credit card. Just US Cash and was perfectly fine.