U. S. citizens need passports to depart or enter the United States and to enter and depart most foreign countries. There are a few exceptions for short-term travel between the United States and Mexico, Canada, and some countries in the Caribbean, where a U. S. birth certificate or other proof of U. S. citizenship may be accepted. But even if people need not have a passport to visit a foreign country, the United States requires one to prove U. S. citizenship and identity to reenter the United States. Hence, travelers need to provide documentation when they pass through United States Immigration upon their return. U. S. passports are the best proof of U. S. citizenship. Travelers may also use one of the following:

• an expired U. S. passport
• a certified copy of a U. S. birth certificate
• a Certificate of Naturalization
• a Certificate of Citizenship
• a Report of Birth Abroad of a Citizen of the United States

All U. S. citizens must have their own passport. Family members may not be included on any passport. This applies to everyone, even newborn babies. To obtain their first passport, citizens must appear in person at one of the 13 U. S. passport agencies, along with a completed Form DS-11, Passport Application. They may also apply for a passport at one of many federal and state courts, probate courts, county/municipal offices, or at U. S. post offices authorized to accept passport applications.

If applying for the first time, applicants who are 16 and older must appear in person when applying for a passport. Minors aged 13, 14, and 15 must also appear in person, and must be accompanied by a parent or legal guardian. Applicants ages 16 and 17 may apply on their own as long as they have acceptable identification. The passport agency may contact their parent or legal guardian to confirm that the parent or legal guardian gives permission to issue the passport. If a passport applicant is a minor and has no identification, then the parent or legal guardian must accompany the applicant. For children under age 13, a parent or legal guardian may appear and apply for a passport on their behalf. If individuals previously had a U. S. passport and wish to obtain a new one, they may be able to apply by mail.

It may take many weeks to process the application for a passport. If possible, individuals should apply for their passport several months before they plan to depart on their trip abroad. If they also need to apply for visas, they need to allow approximately two weeks per visa. Finally, if their U. S. passport becomes altered or mutilated, it may be invalid. If they alter or mutilate it themselves, they may be prosecuted (Section 1543, Title 22 of the U.S. Code).