For a cruise in 2026, the documents required depend on your nationality and the cruise itinerary. For international sailings, a valid passport that does not expire for at least six months after the cruise ends is the "gold standard" and is required for most travelers. Even for "closed-loop" cruises (starting and ending at the same U.S. port), while U.S. citizens can technically use a birth certificate and a government-issued photo ID, cruise lines strongly recommend a passport in case of an emergency that requires you to fly home from a foreign port. You will also need your boarding pass (electronic or printed) and any required visas or electronic travel authorizations for the countries you are visiting. In 2026, many lines also require digital health declarations via their mobile apps. If you are traveling with children who are not your own, you must carry a notarized "Consent to Travel" form signed by their legal guardians. Always keep these documents in your carry-on, as you will need them multiple times during the embarkation process.