There are four or five "big ticket" things that are frequently, and in fact almost always, quoted in U.S. dollars -- hotel rates (but often not restaurant prices at the hotels!), real estate prices, tour rates and rental car/golf cart rates. This is probably because the buyers of these items are usually from the U.S. or other foreign countries. Most everything else that might be used by local residents is quoted in Belize dollars.

But there are exceptions on both sides! If in doubt at all, ask. A taxi driver, for example, might quote a price in Belize dollars but may be happy that you thought he or she meant U.S. dollars.