UPDATED INFORMATION as of June 1, 2009:
A passport, a passport card, a NEXUS, SENTRI or FAST enrollment card, or an enhanced driver’s license is required to travel to Canada, Mexico or the Caribbean by land or by sea. If you do not meet these circumstances you will need a passport to go on a cruise.
If you are on a closed-loop cruise to any of the above destinations, one that begins and ends at the same US port, you do not have to carry a passport and can use your driver’s license and birth certificate instead.
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