Planning a trip with two passports in the mix? Whether you're traveling to Florida to see the grandparents, taking the family on a West Coast cruise, or just navigating school holidays across borders, traveling with dual citizenship often comes with many questions.
While holding both a UK and US passport definitely comes with perks (hello, visa-free travel!), it also means keeping track of who needs to show what and when.
From airport check-ins to documents (like a birth certificate) that may be required for cruises or minor travelers, there are a few rules worth knowing before you head to the airport.
What is Dual Citizenship?
Dual citizenship means that a person is legally recognized as a citizen of two countries at the same time. For UK/US families, this often happens when a child is born in the United States to British parents, or when one parent is American and the other is British.
It can also apply to kids born in the United Kingdom who were registered as US citizens through their American parent(s) even if they've never actually lived in the USA. This process is often done through something called the Consular Report of Birth Abroad (CRBA).
If your child was born outside of the USA, the CRBA acts as proof of their US citizenship — kind of like a birth certificate issued by a US embassy or consulate.
Speaking of which, dual citizenship is more common than ever. In fact, in 2024, over 6,100 Americans applied for British citizenship (the highest number on record!). Whether it’s for family, politics, or practicality, more people are opting to get a second citizenship.
Traveling to the United States
If you’re a U.S. citizen, you must enter and leave the United States using your U.S. passport. No matter how long you’ve lived abroad, how British your accent is, how many baked beans on toast you eat, or how rarely you visit, this rule still applies.
According to the official U.S. Department of State website, “U.S. nationals, including U.S. dual nationals, must use a U.S. passport to enter and leave the United States. U.S. dual nationals may also be required by the country of their foreign nationality to use that country’s passport to enter and leave that country.”
Traveling to the United Kingdom
Returning home is generally more relaxed, but there’s still one key thing: British citizens (even dual ones) should use their UK passport to re-enter the United Kingdom.
This helps avoid being treated as a foreign visitor, which can mean delays at the border, confusion around paperwork, and questions about why you’ve arrived without the right visa.
For example, imagine that your US-born kid flies back to the UK with just their American passport. At immigration, the officer might assume they’re visiting instead of actually returning home. If they don’t have proof of the right to reside, they could face extra checks or even temporary entry restrictions.
If your child is eligible for a British passport but doesn’t yet have one, it’s worth applying before the trip, especially if their home base is the United Kingdom.
Common US/UK Dual Citizenship Mistakes
Even with the best planning, dual citizenship can come with unexpected complications — especially when travel is involved. Let’s take a look at some of the most common blunders.
One of the most common mistakes for families with dual citizens is booking flights under the wrong passport. Airlines often care more about the passport you use when booking the ticket, while immigration cares about the one you use to enter the country.
For example, if your child is departing from the UK, it might seem easier to book their ticket using their British passport. However, if they’re a U.S. citizen, they’ll still need to present their U.S. passport at the border when arriving in the States.
If the booking name and passport don’t match, check-in staff may become confused, so it's best to know which passport you're using for each booking, and keep both on hand.
Another easy mistake is letting one passport expire. It happens — maybe the U.S. one hasn’t been used in years, or the UK one got misplaced and forgotten.
However, when travel day rolls around, you’ll need both to be valid, especially if your child needs the U.S. passport to enter America and the UK one to come back home. Renewals can take weeks (longer if you're applying from abroad), so check well ahead of your travel window.
It’s not just flights that need attention: cruises and land crossings come with their own rules too! Some cruise lines or international rail services may ask for additional documents like a birth certificate, especially if a child is under 16 or traveling with one parent.
It’s always worth double-checking what’s required ahead of time to avoid any awkward check-in drama or last-minute scrambles.
