Most cruise ports require you to carry a photo ID to verify the name on the ship card matches. Even if your cruise is closed-loop, meaning it starts and ends at the same U.S. port, bring your passport. In an emergency, the ship may need to dock at a foreign port, requiring clearance through immigration.

For U.S. citizens, whether you need a passport for a cruise depends on the type of itinerary, specifically if it is a "closed-loop" cruise. A closed-loop cruise is one that departs from and returns to the same U.S. port (e.g., Miami to Miami). Under the Western Hemisphere Travel Initiative (WHTI), U.S. citizens on these specific cruises are often permitted to enter the U.S. with proof of citizenship, such as an original certified birth certificate and a government-issued photo ID, rather than a passport. However, travel experts and cruise lines strongly recommend carrying a passport regardless of the minimum legal requirement. If an emergency occurs—such as a medical evacuation or a missed ship connection in a foreign port—you cannot fly back to the United States from an international location without a valid passport. Additionally, certain destinations like Martinique or Guadeloupe may require a passport just to step off the ship. Relying on just a birth certificate can lead to significant legal and financial headaches if your travel plans are unexpectedly interrupted while you are outside of U.S. territorial waters.