Travelling as a UK Dual Citizen: What Passport to Use and When for Seamless International Travel

As a general rule, use the passport that matches the country you are entering. Enter the UK on a valid British passport or Certificate of Entitlement. Enter your other country of citizenship on that country's passport. For anywhere else, use whichever passport gets you the longest visa-free stay or avoids a visa altogether. It sounds simple, but the details trip people up more often than you would expect, and the rules around proving your status at UK borders have tightened considerably over the past year.

Holding two passports is entirely legal for most UK dual citizens, and the UK does not require you to choose between them. The complication isn't legality, it's making sure the right document is in your hand at the right checkpoint, since carriers and border staff cannot read your mind, only your passport.

Which passport, for which leg of the journey

Situation	Document to use
Travelling to the UK	Valid British or Irish passport, or a Certificate of Entitlement
Entering your other country of citizenship	That country's own passport, where it requires one
Visiting a third country	Whichever passport best meets that destination's entry rules
Naturalised after settling under the EU Settlement Scheme	Your other valid passport or qualifying identity card, linked to your eVisa record
British passport expired	Sometimes accepted alongside an ETA-eligible foreign passport, at the carrier's discretion, though renewal is the safer option

Entering the UK: the ETA does not apply to you, but proof still does

British and Irish citizens, including dual citizens, are exempt from needing a UK Electronic Travel Authorisation. That exemption has not changed. What has changed is enforcement. Since 25 February 2026, carriers have been required to check passenger details electronically against Home Office records before boarding, and a foreign passport alone does not confirm British status in that system. If you turn up with only your other country's passport, you risk extra checks or being denied boarding, because the airline has no automated way to see that you are British.

A valid British passport remains the simplest way to avoid this entirely. If yours has expired or you have never held one, a Certificate of Entitlement (currently £589) proves your right of abode when travelling on a foreign passport, and certificates granted from 26 February 2026 no longer expire, though the linked foreign passport itself still needs to stay valid and up to date on your UKVI account.

The EU Settlement Scheme exception

If you naturalised as British after settling under the EU Settlement Scheme, current guidance lets you travel on your other valid passport or a qualifying EEA or Swiss identity card instead of a British one, provided your eVisa record is up to date.

This is a narrower exception than people assume, and it does not apply to every British dual national, only those who naturalised via that specific route. How you originally acquired your citizenship, and how Brexit continues to affect that group, genuinely changes what you can rely on at the gate.

The European side: what's actually live, and what isn't

The EU's Entry/Exit System became operational in April 2026, recording entries, exits and biometric data for eligible non-EU short-stay travellers. British-EU dual citizens travelling on their EU passport are generally exempt from this, since they are not treated as third-country nationals at that border.

ETIAS is a different story, and this is where a lot of current advice online is now out of date. The EU had been targeting the last quarter of 2026 for launch, but that target was dropped in mid-2026 after the agency building the system concluded it wasn't achievable, and as things stand there is no confirmed launch date, with 2027 now the more realistic expectation.

Do not apply through any website claiming to offer ETIAS registration before the official EU portal opens. If you hold an EU passport as one of your two citizenships, none of this affects you anyway, since ETIAS is only for visa-exempt non-EU nationals.

Practical points that cause the most problems

Carry both passports on any trip where you might need either, and make sure the names and biographical details match across both documents, since a discrepancy is one of the more common causes of delay at a border. If you're travelling with children who also hold dual citizenship, check each child has the correct document for each leg individually, rather than assuming a family group all travels on the same passport type.

It's also worth knowing that UK consular assistance is generally unavailable while you're in the other country whose citizenship you hold, since that government treats you as one of its own nationals rather than a foreign visitor. That's a genuine practical limitation, not a technicality, and it's worth factoring in if you're travelling somewhere where you might need support.

Frequently asked questions

Do dual citizens need a UK ETA?

No. British and Irish citizens, including dual nationals, are exempt, but you still need to show a valid British passport or Certificate of Entitlement when travelling to the UK.

Which passport should I use to enter the UK if I'm not sure?

Use your British passport if you have a valid one. If you don't, a Certificate of Entitlement linked to your other passport is the recognised alternative, and the EU Settlement Scheme exception may apply in narrower circumstances.

Do I need ETIAS to travel to Europe right now?

No. ETIAS has not launched and has no confirmed date, so current entry rules for the country you're visiting still apply as normal.

Get your documents sorted before you book

A mismatch between your citizenship and the passport in your hand at the gate is an entirely avoidable problem. If you're unsure which document applies to your situation, or your British passport has lapsed, Athi Law can advise on your nationality status and travel documents through our immigration team.

We also support clients with related matters during long periods abroad, from conveyancing on property back home to wills and probate planning that accounts for assets or family in more than one country, and family law advice where travel involves children and separated parents. Contact us before you book if anything here doesn't feel settled.