The American Citizen Services unit reminds U.S. citizens not to travel outside the United States without a valid U.S. passport. While dual citizens may be able to travel abroad on a German or other foreign passport, all U.S. citizens are required to present a valid U.S. passport to (re-)enter the United States. Trying to return to the United States while traveling as a dual citizen with only a foreign passport and/or a recently issued U.S. Certificate of Naturalization can result in denial of boarding and significant trip delays and unexpected costs until the traveler could obtain an emergency U.S. passport.
Per Section 215 of the U.S. Immigration and National Act (8 U.S.C. 1185), it is unlawful for a U.S. citizen to enter the United States on anything other than a U.S. travel document. This applies to all dual citizens, including babies and children. U.S. citizens are prohibited from using the ESTA Visa Waiver Program or traveling on a U.S. visa in lieu of a carrying a valid U.S. Passport. Likewise, a dual U.S. citizen who is also a citizen of a European Union member nation must enter the EU on their EU passport.
Always ensure your U.S. passport is valid, and always carry your U.S. passport when traveling to/from the United States. The State Department recommends all U.S. citizens renew their passports at least NINE MONTHS before the expiration date, as many countries now require six months’ validity to enter.