There are countries which U.S. citizens can travel without any form of passport book, passport card or other additional citizenship documentation. U.S. territories, such as Guam, Puerto Rico, U.S. Virgin Islands and American Somoa are countries where no passport or travel documentation is required. To visit these countries a U.S. citizen only needs to show a state-issued photo identification card or driver's license.
The WHTI gives U.S. citizens access to Canada and Mexico without requiring a passport book when traveling by land or sea. A passport card is accepted and is a smaller and cheaper version of a passport that can be used to travel to countries listed on the WHTI by motor vehicle, foot or boat. Alternative WHTI compliant documentation is also accepted when traveling this way to Canada or Mexico.
Just like when traveling to Canada and Mexico, U.S. citizens can access the countries without having a passport book when not flying. Since it is impossible to drive to these islands, a passport card will be the only accepted form on identification that can be used to visit by sea.
When traveling to countries that are part of the Western Hemisphere Travel Initiative you will need to have proper documentation with you before you are allowed to cross the border to another country. Passport books can be used for all air travel to these countries and a passport card can be used for land and sea travel. Other compliant documentation includes an enhanced drivers license or be a member of a certain group. The EDL is issued in Washington, New York, Vermont and Michigan and denotes country of citizenship. Members of the U.S. Military, native Americans and merchant marines can travel into these countries with proof of membership.
