For most travelers in 2026, a passport is strongly recommended, but for U.S. citizens on specific itineraries, it may not be strictly required. If you are a U.S. citizen on a "Closed-Loop" cruise—one that begins and ends at the same U.S. port (like Miami to the Bahamas and back to Miami)—you can technically board with a government-issued photo ID (like a Driver's License) and an official certified Birth Certificate. However, Royal Caribbean and the U.S. State Department advise against this because if you miss the ship in the Bahamas or have a medical emergency that requires you to fly home, you cannot board an international flight without a valid passport. For non-U.S. citizens or for cruises that start in one port and end in another (e.g., San Juan to Miami), a valid passport is mandatory for all guests. In 2026, the Bahamas has also introduced more streamlined "Digital Travel Health" checks, and having a passport with at least six months' validity remains the "gold standard" to ensure you aren't denied boarding or delayed at customs.