Dual citizenship, also known as multiple citizenship or dual nationality, means that a person is a citizen of two countries at the same time. Dual citizenship can happen automatically in certain circumstances (like when a child is born to foreign parents in the United States, and the child therefore becomes a citizen of the U.S. and the parents’ home nation). Likewise, if a child has parents that are U.S. citizens but are born overseas, she may automatically become a citizen of both the U.S. and the foreign country.
One can also apply for dual citizenship. If a foreign national has permanent residency in the United States (for example, if she is a green card holder) for at least three years and has been married to a U.S. citizen, she may be able to apply for dual citizenship through a legal process.

What Countries Allow Dual Citizenship?

The United States does not encourage dual citizenship, but it allows one the right to retain dual citizenship if you have been a dual citizen from birth or childhood, or you became a citizen of another country after already having U.S. citizenship.
There are a number of countries that allow dual citizenship (such as Germany, South Africa, Portugal, and Turkey, to name a few) and many that do not (such as Austria, Indonesia, Ecuador, and Venezuela). Further, there are some countries that only allow dual citizenship with specific countries. For example, Spain allows dual citizenship with some Latin-American countries, but not with the United States.

What If I’m a Naturalized Citizen?

The situation is slightly unclear for persons who have become a U.S. citizen by naturalization and still use their old citizenship. This is because when you go through a U.S. naturalization process, you are required to state under oath that you are renouncing your old citizenship. People that act inconsistently with this pledge, such as using their passport from their renounced country, can theoretically lose their U.S. citizenship. The State Department is however no longer actively pursuing such cases.

What Kind of Confusion Can Multiple Passports Generate?

If you possess multiple passports, you can create confusion during your flight check-in, even if you are legally a dual citizen of two countries.
When you have more than one passport and you leave the U.S. by air, the airline officials will want to see your passport or other proof of citizenship. To ensure that you will be allowed to enter the next country on your trip, the airport will also want to see relevant visas in your possession.

Things can get complicated when you’re a dual citizen with multiple passports in the following ways:

  • If you show the airline your U.S. passport, you will be asked for the visa to enter your destination country. However, because you are a national of your destination country, you don’t need a visa. To prove that you are a dual citizen, you will have to bring and show your second passport.
  • If you start by showing them your passport from your destination country, you’ll then be asked to hand in your I-94 (this is the U.S. temporary visa record that airlines are supposed to collect from aliens leaving the U.S.) or show your resident alien ID ("green card"). In this situation, you’ll have to show your U.S. passport in order to show why you don’t need or have a green card or an I-94.

Traveling with Multiple Passports as a Dual Citizen

If your travel destination is your other country of nationality, travel with both your U.S. and travel destination passports. When showing your documentation to airline officials, it’s best to show the same documents as what you show immigration officials as well as your U.S. passport. U.S. law requires its citizens to be in possession of a U.S. passport or other proof of citizenship when leaving the country.

Do I Need an Immigration Attorney?

Dual citizenship and travel are complex issues that have specific legal obligations. For this reason, it’s a good idea to seek counsel from a skilled immigration attorney to ensure that you properly obtain dual citizenship.