For international travel, excluding cruises that begin at and return to the same U.S. port, U.S. CITIZENS MUST HAVE A VALID PASSPORT. For cruises that begin at and return to the same U.S. port, U.S. CITIZENS must have a VALID PASSPORT or original certified birth certificate w/raised seal and photo ID. NON-U.S. CITIZENS and RESIDENT ALIENS should contact their respective embassies and U.S. Immigration for applicable regulations.