On June 1, 2009, the U.S. government will implement the full requirements of the land and sea phase of Western Hemisphere Travel Initiative (WHTI). The proposed rules require most U.S. citizens entering the United States at sea or land ports of entry to have a passport, passport card, or WHTI-compliant document http://www.dhs.gov/xtrvlsec/crossingborders/.
Please Note: Children under age 16 will be able to continue crossing land & sea borders using only a U.S. birth certificate (or naturalization certificate) after the new law takes effect in June. The original birth certificate or a copy may be used. See the Department of Homeland Security's Ready, Set.. Go! http://www.cbp.gov/xp/cgov/travel/vacation/ready_set_go/ for more information on the changing travel requirements.
For complete, up-to-date and official information on current passport requirements, please visit: http://travel.state.gov.