U.S. passports are blue booklets issued to citizens by the government for all travel abroad. Passports are a way to prove your identity as well as citizenship. There are also passport cards, which is a government-issued travel document that allows citizens entrance into Mexico, the Caribbean and Canada. Passport cards are less expensive but can not be used for sea travel beyond the Western Hemisphere. Cruise Mates recommends that travelers apply for a passport prior to going on a cruise because it is accepted at all cruise ports and, "in case of emergency if one must return home by air, a passport is the only accepted document."
A closed-loop cruise is a cruise that begins and ends at the same port in the United States and has returned from a contiguous territory (countries that share a border with the United States, such as Mexico or Canada) or an adjacent island (most of the Caribbean Islands). If you are a citizen on a closed-loop cruise you will be able to travel with just a birth certificate and a government-issued picture ID that has your name and date of birth. However, you must return on the same ship that you departed on.
If you are a citizen of another country you must possess a valid passport from your country of origin as well as a visa. It is not unusual for a non-U.S. citizen to have to surrender a passport upon arrival for immigration inspection. However, some non-U.S citizens may be eligible to apply for the Visa Waiver Program. The program allows citizens from 36 participating countries to enter U.S. territory for up to 90 days without a visa. However, a valid passport is still needed.
