Passports are required for any cruises that visit outside the United States or US territories. This includes popular cruise destinations such as the Bahamas, most of the Caribbean, Mexico and Canada, according to the U.S. State Department.
Since the passage of the Western Hemisphere Travel Initiative Act of 2004, U.S. citizens must show a passport or passport card when entering the United States from popular cruise destinations such as Mexico and the Caribbean, which previously only required a photo ID.
Closed-loop cruises that depart from the United States, stay in the Western hemisphere and return to the same U.S. port only require a photo ID and proof of citizenship, says the U.S. State Department. However, passengers should check with the cruise line about specific requirements at each port of call.