Brexit has gone largely unnoticed by many UK residents unless you’re running a business or travelling abroad.

If you’re originally Spanish and have British citizenship in the UK, you must take steps to keep your Spanish nationality.

Losing Spanish nationality comes as a surprise to many Spanish nationals living in Great Britain.

This user-friendly guide is designed to help Spanish nationals obtain an apostille—legal jargon for a Certificate of Authentication—for their UK Certificate of Naturalisation and formally apply to state their intention to retain their Spanish nationality.

Brexit and dual citizenship

After Brexit, the UK ceased to be an EU member state and is now classified as a third country by Spain.

Spanish citizens who also become British nationals are subject to Spanish regulations covering dual citizenship with countries outside the EU.

Spain doesn’t allow dual citizenship with non-EU countries, so it’s essential for Spanish nationals in the UK to declare their intent to retain their nationality, or they could lose it.

What’s the position in Spanish law?

As a starting point, it’s helpful to understand the legal position.

Article 24 of the Spanish Civil Code states that:

Article 24 doesn’t apply to Ibero-American countries, Andorra, the Philippines, Equatorial Guinea, or Portugal, but it does apply to the UK.

You must declare your intention to retain your Spanish citizenship within three years of acquiring your UK nationality, or you will lose it.

Starting the process to retain Spanish citizenship

To retain Spanish citizenship, you must submit a Declaration of Intent at the Spanish Consulate General, which has two locations:

London and Manchester.

Which one you use depends on where you live.

Submissions must usually be made in person, but some consulates will accept applications by post. You can check this when you contact them. It’s not possible to apply online.

Before you start the process, you’ll need a UK apostille certificate for your Certificate of Naturalisation; this is issued by the Foreign & Commonwealth Office (FCDO) and must be done before you attend your consulate appointment.

Making an apostille application

To do this, you’ll need an FCDO registered solicitor, and the easiest way to find one is to use the free search on the Law Society website.

Most lawyers advertise their services online, so checking if they offer this is easy, but ask them to ensure they are FCDO-registered. Not all solicitors are.

Usually, the solicitor copies the original Certificate of Naturalisation and then certifies the copy. However, the solicitor still needs to see the original to make a copy.

Next, you’ll apply to the FCDO Legalisation Service for the apostille certificate.

You can apply online or by post; if you apply online, your supporting documents must still be mailed. The application form is sent with the Certificate of Naturalisation.

This is the only way to apply; no ‘in-person’ service exists.

Applications via the FCDO websites take about 3-4 weeks to complete.

What documents do you need to apply to retain Spanish citizenship?

As well as the UK Certificate of Naturalisation (apostilled), you will also need the following:

  • Completed Declaration of Retention Form
  • Valid Spanish passport
  • Proof of UK residence includes utility bills, bank statements and a UK passport if you have one.
  • Passport-sized photographs
  • Marriage certificate if you have changed your name
  • Spanish National Identity Card (DNI)

Any documents not in Spanish must be accompanied by a sworn Spanish translation from a translator recognised by the Spanish Ministry of Foreign Affairs.

Common pitfalls in this process

There are plenty of holes in this process, and mistakes can be costly and delay your application. Here is a checklist to help you stay on the right path.

  • Before you start, check with the consulate to find out precisely what they need.
  • Only original documents are accepted for the consulate process and the apostille, so don’t use copies.

    Exception: A certified and apostilled copy of your Certificate of Naturalisation will be accepted.

  • Copy everything you send, so keep meticulous records, including any correspondence.
  • Documents like your Spanish passport must be in date. There may also be time restrictions on birth and marriage certificates – check this before applying.
  • Plan ahead; sometimes, you can wait months for a consulate appointment, so be aware of the three-year deadline; it runs from the date you acquired UK citizenship. Apostille services can also be slow.

What happens if I don’t do this?

If you don’t follow the process within three years, you will lose Spanish citizenship and all the rights attached to this, including living and working in Spain and other EU member countries.

The Spanish authorities may revoke your Spanish passport and ID card, and if you return to Spain, you’ll have problems accessing healthcare, social services, and education.

It is possible to recover Spanish citizenship, but this is a complex and lengthy legal process. It’s far easier not to lose it in the first place.

Why use us?

You’re right if you think the process looks complex and daunting. It’s far easier to find a professional to handle this for you, but choosing the right company is essential.

We specialise in obtaining apostilles for UK documents required by international authorities and have years of experience managing UK Certificates of Naturalisation for use in Spain.

We make the whole process quick and painless – we can obtain an apostille in as little as one day -and our dedicated team is with you every step of the way.

You also won’t have to worry about safety as our protocols ensure your documents are always secured and confidential from start to finish.

If needed, we start with an initial consultation to assess your situation. This is entirely free and without obligation.

What service we offer:

We certify a copy of your Certificate of Naturalisation through our FCDO-registered solicitor. Apostille processing takes just 1–2 working days.

You can also order a sworn Spanish translation of your certificate, usually ready within 24 hours. You can use the digital copy—simply print it out; no original signature from the translator is needed. 

Frequently asked questions

No, you don’t need to live in Spain, but you must declare your intent at the Spanish consulate, which corresponds to your residence abroad.

Online submissions are not accepted; you can only apply in person or by post.

The apostille doesn’t have an expiry date. However, documents that are not recent are sometimes not always accepted. This can be caused by delays in preparing your application, followed by a long wait for an appointment. Check this with the consulate first and find out if there are any time restrictions on certain documents.

If your children are under 18 (referred to as minors) and have Spanish nationality, you should discuss this with the consulate or a specialist legal adviser who can provide advice on your situation.

It can take several weeks to a few months, depending on the complexity of your case, the processing time for apostille certificates and how quickly you can make an appointment with the consulate.

Spanish citizenship can be lost automatically if you don’t declare your intention to retain it within three years. Regaining citizenship is possible, but it is a complex and potentially expensive process that may require you to reside in Spain.

Retaining Spanish citizenship won’t impact your British citizenship if you have dual nationality.

This article has been written by experts and fact-checked by experts. We only link to high-quality sources like government information & data, original reporting and interviews with industry experts. Reputable publishers are also sourced and cited where appropriate to support the facts within our articles.

Hague Apostille and Legalisation
https://www.exteriores.gob.es/Consulados/londres/en/ServiciosConsulares/Paginas/Consular/Legalizacion-y-Apostilla-de-La-Haya.aspx

Spanish Civil Code
https://data.globalcit.eu/NationalDB/docs/spanish-civil-code-ENG%202013.pdf

Preservation of Spanish nationality
https://www.exteriores.gob.es/Embajadas/bangkok/es/Comunicacion/Noticias/Paginas/Articulos/Conservaci%C3%B3n-de-la-nacionalidad-espa%C3%B1ola,-art–24-del-C%C3%B3digo-Civil-.aspx

Spanish nationality law
https://en.wikipedia.org/wiki/Spanish_nationality_law

Act 36/2002, Of 8 October, Amending The Civil Code In Matters Of Nationality.
https://www.global-regulation.com/translation/spain/1450837/act-36-2002%252c-of-8-october%252c-amending-the-civil-code-in-matters-of-nationality.html

What is a Certificate of Naturalisation? [New Guide]
https://apostillelondon.com/blog/what-is-a-certificate-of-naturalisation/