What is Double Taxation?

Double taxation occurs when the same income is taxed twice — once in the country where it arises (the source country) and once in the country of residence (the residence country). Without protection, a British national living in Mijas who receives a UK private pension could potentially face tax on that pension in both the UK and Spain. Double taxation treaties (DTTs) are bilateral agreements between countries designed to prevent this from happening — they allocate taxing rights over different types of income between the two countries.

Spain's Double Taxation Treaty Network

Spain has one of the most extensive DTT networks in Europe, with over 90 treaties in force. The most relevant for Costa del Sol residents include:

  • Spain-UK (1975, amended): Covers pensions, employment income, dividends, interest, and capital gains. Particularly important for British residents in Spain post-Brexit.
  • Spain-Germany: Covers all common income types; important for the large German-speaking expat community on the Costa del Sol.
  • Spain-Netherlands, Spain-Belgium, Spain-Sweden, Spain-Denmark, Spain-Norway: Relevant for Scandinavian and Benelux expats.
  • Spain-USA: Covers US citizens resident in Spain — the US taxes its citizens on worldwide income regardless of residency, making this treaty particularly complex.
  • Spain-France, Spain-Italy: Relevant for French and Italian nationals.

How DTTs Work: Exemption vs Credit Methods

DTTs eliminate double taxation using one of two main methods:

  • Exemption method: Certain income is taxed only in one country — the treaty allocates the exclusive taxing right. For example, under many treaties, government pensions are taxed only in the country that pays them.
  • Credit method: The income is taxed in both countries, but the residence country (Spain) allows you to deduct the tax paid in the source country from your Spanish tax bill. You pay the higher of the two tax rates, but never both in full. Spain uses the credit method extensively.

Specific Income Types: UK-Spain Treaty Guide

For British nationals resident in Spain, the key allocations under the UK-Spain DTT are:

  • UK government/civil service pensions (including NHS, armed forces, police, teachers): Taxed only in the UK. Not subject to Spanish IRPF, but must be declared in Spain for progressivity purposes.
  • UK state pension and private/company pensions: Taxed in Spain (as country of residence) only. Spain has the exclusive right under the treaty. The UK should not withhold tax on these — you may need to apply to HMRC for the income to be paid gross and file a Spanish IRPF return declaring it.
  • UK rental income: The UK may tax this at source (as the property is in the UK). Spain also taxes it (as worldwide income of a Spanish resident). You claim a credit in your Spanish IRPF for the UK tax paid.
  • UK dividends: The source country (UK) can withhold up to 15% (standard shares) or 10% (substantial holdings). Spain taxes the dividends on your IRPF return and allows credit for the UK withholding.
  • Employment income from UK employer while working in Spain: Generally taxed in Spain if you are habitually resident and working here. May be partially allocated to the UK if you spend time physically working in the UK.

Practical Steps to Avoid Double Taxation

To benefit from DTT provisions, you typically need to:

  1. Obtain a certificate of Spanish tax residency (certificado de residencia fiscal) from the AEAT — this proves to the source country's tax authority that you are resident in Spain.
  2. Submit the certificate to the source country's tax authority (e.g., HMRC in the UK, Finanzamt in Germany) to claim exemption from withholding or reduced withholding rates under the treaty.
  3. Declare all worldwide income in your annual Spanish IRPF return, claiming double taxation relief credits for taxes paid abroad.
  4. File any required returns in the source country (e.g., the UK Self Assessment return, if required).

The interaction between two tax systems is complex and the practical outcome depends on the specific treaty provisions, the type of income, and your personal circumstances. We always recommend working with a tax advisor who is familiar with both the Spanish IRPF system and the tax system of your home country.

Frequently Asked Questions

Under the Spain-UK Double Taxation Treaty, UK state pension income is taxable in Spain (the country of residence) not in the UK. You should inform HMRC of your Spanish residency (using form Spain-Individual or similar) so that your state pension is paid gross without UK tax deducted. You then declare and pay Spanish IRPF on the pension income in Spain. Note: UK government pensions (civil service, NHS, armed forces, police, teachers) are treated differently — they are taxed only in the UK regardless of where you live.
A certificate of Spanish tax residency can be requested online from the AEAT (Agencia Tributaria) website using your NIE number and digital certificate or Cl@ve PIN access. The AEAT typically issues the certificate within a few days. It confirms you are a Spanish tax resident for a given year and can be submitted to foreign tax authorities to claim treaty benefits. Your tax advisor can obtain this on your behalf.
If there is no DTT between Spain and your home country, you may face double taxation — both countries can tax the same income under their domestic rules. However, Spain's domestic IRPF law includes unilateral relief provisions (deducciones por doble imposición internacional) that allow a credit for taxes paid abroad even without a treaty, typically limited to the Spanish tax that would have been due on that income. The amount of relief available is limited, so the net position may still involve some level of double taxation in some cases.