Dual British–Spanish Children and Travel to the UK: Understanding Your Rights Under the ETA System

With the rollout of the UK ETA (Electronic Travel Authorisation) system, many families are confused about how dual British–Spanish children should travel to the UK. Official guidance, introduced in February 2026, suggests that dual nationals should hold a British passport or a certificate of entitlement, but this is a recommendation, not a legal requirement. Understanding the difference between what is legally required and what is advised can help families make informed decisions and avoid unnecessary costs or stress.

If your child holds both Spanish and British nationality, you may have seen UK government guidance suggesting they should travel with a British passport or a certificate of entitlement. While this may make travel smoother, it is important to understand that this is a recommendation and not a legal requirement.

Your child is fully entitled to enter the UK using their Spanish passport and a valid ETA. The UK guidance, introduced in February 2026, is intended to avoid practical issues at the border, but it does not override your child’s legal rights as a Spanish citizen. The requirement to obtain a British passport or certificate of entitlement is therefore optional and not mandated by law, although the certificate currently carries a cost of £589, which may be significant for some families.

Some children may not yet have applied for a British passport, and in such cases, the guidance creates a practical suggestion rather than a legal obligation. The intention of this explanation is simply to highlight that, under the law, dual nationals with a Spanish passport are entitled to travel with ETA, and the UK suggestion should be understood as a measure to make travel easier rather than a compulsory requirement.

For families who wish to formally raise this argument with the UK Home Office or airlines, a sample letter outlining the points above has been drafted and is available Letter to the British Home Office. This can be used as a reference to present the facts clearly and respectfully when seeking clarification or challenging unnecessary administrative requirements.

Taken from the Home Office fact sheet of March 2026. Full information found on the link at bottom of page:
“Why are you changing passport rules for dual citizens?

“The UK is moving to a modernised ‘digital permission’ system where international carriers are required to confirm, through automated checks against Home Office records, that passengers have valid permission or status to travel to the UK. All carriers (e.g. airlines, maritime and rail) have now been equipped with the necessary tools to verify travel permission via automated digital checks with the Home Office.
We recognise that this is a significant change for carriers and travellers, but we have been clear on requirements for dual British citizens to travel with a valid British passport or Certificate of Entitlement, in line with those for all British citizens.
Public information strongly advising dual citizens to travel with a valid UK passport or Certificate of Entitlement has been available since October 2024, including official guidance on GOV.UK.
We have delivered a comprehensive range of communications and engaged with an extensive network of stakeholders, including global carriers and operators. We have sent emails to those impacted we hold valid contact details for. And we have included information for dual citizens in our ETA communications campaign which has been running since 2023.
Can dual British citizens use alternative documents as proof of citizenship?

We recognise this is a significant change for carriers and travellers, and so we have provided additional temporary guidance to carriers on possible alternative documentation, including expired passports issued in 1989 or later and alongside a valid non-visa national third country passport where biographic details match. It is an operational decision whether carriers accept alternative proof, and if so, what alternative proof they will accept.
We strongly recommend that passengers should obtain a British passport or Certificate of Entitlement to ensure the smoothest travel experience.
Certificates of Entitlement will be issued in digital format. This means that a certificate only needs to be applied for once, rather than expiring with your passport.
In line with current practice, on arrival at the UK border, Border Force will still assess a person’s suitability to enter the UK and conduct additional checks if required.
What happens if a dual British citizen needs to travel in an emergency?

Individuals who have previously had a British passport can apply for an emergency travel document if they urgently need to enter the UK”.

Apply for an electronic travel authorisation (ETA)

Please note: The information provided is based upon our understanding of current legislation. It is not legal advice but is provided freely to enable you to be properly informed. We recommend that if you are considering taking action, you should seek professional advice.