Which Passport Should You Travel On?
If you hold two passports, the one you use decides which authorization you need — and some countries require you to use theirs. How dual nationals choose correctly.
The authorization follows the passport
Every electronic authorization is tied to a specific passport, so the choice of passport decides the requirement. A traveler eligible for a US ESTA on one passport but not the other must apply with the qualifying one. The same logic applies to ETIAS, the UK ETA, and the rest: eligibility is judged on the nationality of the passport you present, not on the other citizenships you happen to hold. For the ETIAS-specific version of this question, see our dual nationals and ETIAS guide.
Use each country's passport for that country
The widely followed convention is to enter and exit a country on its own passport where you are a citizen. Present the destination's passport at its border, and your other passport elsewhere. Some countries make this a legal requirement rather than a matter of convention.
The United States: a firm rule
US law requires US citizens — including dual nationals of every age — to enter and leave the United States on a valid US passport. A dual citizen cannot travel to the US visa-free on a foreign passport: US citizens are not eligible for an ESTA, and the authorities cancel any ESTA found to belong to a US citizen. US citizens are also ineligible for US visas. If you are a US citizen, travel to the US on your US passport and keep it valid.
The United Kingdom and Ireland
British and Irish citizens, including dual citizens, do not need and cannot use a UK ETA. If you hold British or Irish citizenship, travel to the UK on your UK or Irish passport, or a document proving your right of entry, rather than applying for an ETA on a third passport.
How it works in practice
Booking and boarding follow the passport you will use to enter your destination, so book your ticket in the name and details of that passport. At the airport you may show one passport to the airline and the departure country and a different one on arrival. Carry both valid passports whenever you travel between two countries where you hold citizenship, and be ready to present each at the right point.
Watch the expiry dates on both
A dual national's weak link is often an out-of-date second passport. If you must use a particular country's passport to enter it, that passport has to be current — an expired one is not a fallback. Check the validity of every passport a trip will need, and renew early, since a renewal also means any authorization tied to the old passport must be obtained again — see why your authorization is tied to your passport.
Names that differ between passports
If your two passports show different names, keep both with you and make sure your booking matches the passport you will enter your destination on. A mismatch between ticket, authorization, and passport is a common cause of trouble at check-in.
Sources
U.S. Department of State — dual nationality; the UK ETA — gov.uk; and the official application site for each authorization, including ESTA and the ETIAS portal.
About this page
This is general information, not legal or immigration advice; dual-nationality rules vary by country, so confirm your situation with the relevant government before you travel.