US dollars are widely accepted on all Caribbean islands. Just make sure that taxi drivers etc are quoting in US and not local dollars. Take small denomination notes to make getting change easier and be aware of the local dollar to US dollar exchange rate.
US dollars accepted. Your may receive change in Carribean dollars, use in duty free shops on islands. Dont take large denomination notes they never have enough change.
US dollars and when in taxi's etc, make sure you agree the fare and don't fall for 'hard-luck' stories from the drivers.
US small denomination $ for the taxis. All cards can be used in the shops.