The Belize dollar is fixed at BZ$2 to USD $1, and USD cash is widely accepted in tourism hubs. Expect change in Belize dollars. Cards are common at larger hotels, dive shops, and restaurants in Belize City, San Pedro, Caye Caulker, and Placencia, but small boats, reserve fees, tips, and local cafes still reward carrying cash.
ATMs are reliable in Belize City, San Pedro, and Placencia, thinner on Caye Caulker, and effectively absent once you move onto outer islands or all-day boat programs. Withdraw before shifting to small islands, liveaboard-style lodges, or multi-day southbound itineraries.