Which Passport Should a Dual US Citizen Use? The 2026 Travel Rules

A dual citizen does not choose one passport for an entire trip. The correct document changes with the border being crossed.

For a US citizen, one rule is fixed: use a valid US passport to enter and leave the United States. Your other country may impose a matching rule at its border. The airline may need to see both documents because it is checking whether it can legally carry you to the destination, not deciding which nationality you possess.

This guide answers the document question. For the wider legal and tax position, use our complete guide to dual citizenship for US citizens.

The United States requires the US passport

The State Department says that US nationals, including dual nationals, must use a US passport to enter and leave the United States. Customs and Border Protection applies the same rule to adults and children.

That means a US dual citizen should not try to enter the United States using:

• A foreign passport with a US visa.
• A foreign passport with ESTA.
• A foreign residence card without a US passport.
• A foreign passport merely because it is newer or has more remaining validity.

US citizens are not eligible for US visas. CBP also warns that ESTA applications belonging to US citizens can be denied or cancelled. A second nationality does not turn an American into a foreign visitor at the US border.

Your other country may require its passport

The second half depends on the law of the other country. Some governments require their citizens to enter and leave using that country’s passport or national identity document. Others permit more flexibility.

Before travel, confirm the rule through the foreign country’s embassy, consulate or immigration authority. Do not rely only on an airline forum or a travel agent. A dual national can face obligations that do not apply to ordinary tourists, including registration, military service, exit controls or limits on foreign consular assistance.

If both countries require their own passports, carrying two is normal:

1. Present the US passport when interacting with US border authorities.
2. Present the other country’s passport when its border authorities require it.
3. Keep both available at airline check-in and boarding.

Using the foreign passport at the foreign border does not, by itself, threaten US citizenship. US nationality is not lost merely because a dual citizen uses the travel document of another country.

Airline check-in is not the same as border control

Airlines can be fined or required to transport a passenger back when the passenger lacks the documents needed for the destination. Their systems therefore focus on admission documents.

Suppose a US and EU dual citizen flies from New York to an EU country:

• At airline check-in, the EU passport proves the right to enter and remain in the EU without a visa.
• At US departure processing, the traveler should have the US passport available.
• At the EU border, the EU passport establishes EU citizenship.
• On the return, the US passport proves the unrestricted right to enter the United States.

The reservation name should match the travel document used for the airline booking as closely as possible. If the passports show different names, carry the legal document connecting them, such as a marriage certificate or court order, and ask the airline about its record requirements before departure.

Dual-citizen children need the same planning

The State Department says that a child who is a US citizen is not eligible for a US visa, even if the parents have never documented the child’s citizenship. A US-citizen child needs a US passport for travel to and from the United States.

Parents should resolve citizenship evidence and passport issuance before booking. A foreign passport or an ESTA is not a substitute. When only one parent travels with the child, destination-country consent and custody-document rules may also apply, separately from nationality.

What if the US passport is expired?

Do not assume the foreign passport solves the problem. Contact the nearest US embassy or consulate before travel and ask about the appropriate passport service. CBP recommends renewing well before booking.

Emergency passport procedures exist, but eligibility and timing depend on the facts and location. An airline may refuse boarding before a US border officer ever sees the case.

A practical two-passport checklist

Before departure:

• Check the validity and blank pages in both passports.
• Confirm the passport rule for each country of citizenship.
• Check transit-country rules, not only the final destination.
• Make the airline booking under a name the carrier can reconcile to the documents.
• Carry evidence connecting different names.
• Obtain a US passport for every US-citizen child.
• Keep digital copies separate from the originals.
• Do not apply for ESTA or a US visa as a US citizen.

The broader risk is not having two passports. It is treating one as though it erases the legal obligations attached to the other. Our guide to dual citizenship and consular protection explains what can happen when the second country treats you only as its citizen.

The Civita view

A second passport can expand residence and travel rights, but it should be modeled as a legal status rather than a travel accessory. The useful question is not which passport looks stronger. It is which rights and obligations each nationality creates for your family.

If you want the citizenship routes, costs and risks mapped to your situation, start with a Program-Fit Report. Civita provides independent, client-paid analysis and takes no commission from any program, developer or fund.

This guide is general information, not legal advice. Entry rules and passport procedures can change. Confirm the current requirements with the relevant government authorities before travel.