The requirement for a passport for an 8-year-old on a Disney Cruise depends heavily on the ship's itinerary and the port of departure. If you are taking a "Closed-Loop" cruise—one that begins and ends at the same U.S. port (like Port Canaveral or Miami) and travels only to the Bahamas, the Caribbean, or Mexico—U.S. citizens, including children, are technically permitted to travel with just an original state-issued birth certificate. However, Disney Cruise Line and travel experts strongly recommend that all passengers, regardless of age, carry a valid passport. If an emergency occurs and you need to fly home from a foreign port (like the Bahamas) due to illness or a missed ship, a birth certificate is not sufficient for air travel; you would be stranded until an emergency passport is issued at a U.S. Embassy. For cruises departing from or ending in non-U.S. ports (such as European or Alaskan cruises ending in Canada), a passport is mandatory for all ages. Always check the specific documentation tab in the Disney Cruise Line Navigator app before sailing.