For U.S. citizens traveling to and from the United States and Mexico, passports or passport cards are required regardless of transportation method. This means that U.S. citizens traveling to or from Mexico by foot, car, ship, plane or any other mode of transportation are required to display a valid U.S. passport upon crossing the border.
Traditional passports allow U.S. citizens to travel internationally by any transportation mode. Passport cards differ in that they only allow U.S. citizens to travel to Mexico, Canada, the Caribbean and Bermuda, and are only valid for land border crossings or sea ports of entry. The advantage of passport cards is that they are less expensive than traditional passports.
U.S. citizens may apply for a passport in person at any local passport agency or passport acceptance facility. A completed DS-11 passport application form, two passport photos and proof of identification and citizenship are required along with payment of fees. Total fees for obtaining a passport for an adult are $125 as of 2010. Applying for a passport card requires the same process, but fees are $55 for adults.
