It depends on the territory you want to visit, as the Caribbean entry requirements are not standard. Some allow U.S. citizens to enter as tourists, provided they have valid travel documents. Others require visitors to have valid passports and visas.

For U.S. citizens, the need for a passport in the Caribbean depends entirely on how you travel. If you are flying to any Caribbean nation (including the Bahamas and Jamaica), a valid Passport Book is mandatory. However, a popular "loophole" exists for cruise passengers: if you are on a "closed-loop" cruise—one that begins and ends at the same U.S. port (e.g., Miami to Miami)—you can technically travel with just a government-issued birth certificate and a photo ID. This is part of the Western Hemisphere Travel Initiative. Despite this, it is strongly recommended to carry a passport; if you miss the ship or have a medical emergency and need to fly home from a foreign island, you cannot board a plane back to the U.S. without a passport. Furthermore, some specific islands like Martinique, Guadeloupe, and St. Barts have their own strict laws and require a passport for all visitors, meaning the cruise line will deny you boarding if you don't have one. Additionally, U.S. territories like Puerto Rico and the U.S. Virgin Islands are considered domestic travel for Americans, so no passport is required for those specific destinations.