Spain taxes residents on their worldwide income, which can create double taxation when income also arises in — and is taxed by — a foreign country. Spain has an extensive network of bilateral double tax treaties (Convenios para evitar la doble imposición, CDIs) that allocate taxing rights between Spain and the other country and provide relief, primarily through Spain's unilateral foreign tax credit under Article 80 of the IRPF Law, applied consistently with whatever treaty is in force. Newcomers under the Beckham Law special regime are taxed only on Spanish-source income, which changes — and often reduces — the relevance of treaty relief for their foreign income during the years the regime applies.
Newcomers who keep foreign income streams after moving to Spain — a foreign pension, rental income abroad, foreign employment income, or investment income from another country — need to know whether Spain has a treaty with that country and how relief works, so they are not taxed twice on the same income and can correctly claim any credit or exemption on their Spanish return.
Key Facts
Spain maintains a large network of double tax treaties in force with countries across Europe, the Americas, Asia, Africa, and Oceania (commonly cited figures put the number around 90+ agreements), each published with its signing date and Boletín Oficial del Estado (BOE) publication reference on the Agencia Tributaria's "Convenios de doble imposición firmados por España" page, organized by country/region (Source: Agencia Tributaria, Convenios de doble imposición).
Relief from double taxation in Spain is generally delivered through Article 80 of the IRPF Law (Ley 35/2006): for foreign-source income also taxed abroad, the taxpayer deducts the lower of (a) the actual foreign tax paid on that income, or (b) the amount that would result from applying Spain's average effective tax rate to that portion of the foreign income — this is a tax-credit (imputación) mechanism rather than a blanket exemption (Source: Agencia Tributaria, "Deducción por doble imposición internacional").
Individual treaties can also specify an exemption method for certain income categories (e.g., some foreign pensions or specific income types may be exempt from Spanish tax under a treaty's terms, or taxing rights may be allocated exclusively to the source country) — the exact mechanism depends on the specific treaty text and income type, so the applicable treaty must be checked article by article for the relevant income category.
To claim treaty benefits (e.g., a reduced withholding rate in the other country, or to prove Spanish tax residency to a foreign tax authority), taxpayers can request a "certificado de residencia fiscal en España — Convenio" from the Agencia Tributaria, available via the Sede Electrónica or by filing Modelo 01 at the corresponding tax office; this treaty-residency certificate is valid for one year from issue (Source: Agencia Tributaria, "Solicitud de un certificado tributario de residencia fiscal").
Some countries require the certificate embedded into their own specific bilateral form (e.g., Portugal's Modelo 21RFI) rather than AEAT's generic certificate — when a treaty-implementing Order specifies a country-specific form, that form (stamped/signed by AEAT) is used instead of the standard residency certificate.
Beckham Law special-regime taxpayers (see the Personal Income Tax document) are taxed as if non-resident, i.e., only on Spanish-source income; because their regime generally does not tax worldwide/foreign-source income the way ordinary IRPF residency does, the double-tax-treaty credit mechanism under Art. 80 becomes less relevant to their foreign income during the years the special regime applies — though treaty rules can still matter for specific Spanish-source income categories and for the transition years before/after the regime.
To check whether Spain has a treaty with a specific country and read its text, consult the Agencia Tributaria's "Convenios de doble imposición firmados por España" listing (organized alphabetically/by region with links to each treaty text and BOE reference) or the Ministerio de Hacienda's alphabetical CDI listing.
Steps
Identify the relevant treaty — Check the Agencia Tributaria's list of double tax treaties to confirm whether Spain has an agreement with the country where your foreign income arises, and locate the treaty article covering that specific income type (employment, pensions, dividends, rental income, etc.).
Determine which country has primary taxing rights — Read the relevant treaty article to see whether it allocates exclusive taxing rights to one country, or allows both to tax with relief given by the country of residence (usually Spain, for a resident).
Obtain a Spanish tax residency certificate if needed — If a foreign payer or tax authority needs proof of Spanish residency to apply a reduced withholding rate or treaty benefit at source, request the "certificado de residencia fiscal — Convenio" from AEAT (via Sede Electrónica or Modelo 01).
Claim the foreign tax credit on the Spanish return — When filing the annual Renta declaration, claim the Article 80 deduction for foreign tax paid on income also taxed in Spain, limited to the lower of the actual foreign tax or the equivalent Spanish average rate on that income.
Timelines
Tax residency certificate (Convenio) validity: 1 year from date of issue
Required Documents
Proof of foreign tax paid (foreign tax return/receipt) to support the Article 80 credit claim
Certificado de residencia fiscal en España — Convenio (if required by the foreign payer/authority), requested via Sede Electrónica or Modelo 01
Country-specific treaty form where required (e.g., Portugal's Modelo 21RFI), stamped by AEAT
Common Mistakes
Assuming a double tax treaty automatically means "no tax owed anywhere" — most treaties allocate rights and provide a credit mechanism, not a blanket exemption, and Spain's default relief method (Art. 80) is a credit capped at the lower of actual foreign tax or Spain's average rate on that income.
Not requesting a Spanish tax residency certificate before a foreign payer applies withholding, resulting in over-withholding abroad that then requires a separate reclaim process.
Assuming Beckham Law status eliminates all foreign tax considerations — it generally removes Spanish tax on non-Spanish-source income, but specific Spanish-source income and transition-year situations can still involve treaty questions.
Not checking the specific treaty article for the income type in question, since treatment can differ significantly between, say, employment income, pensions, and dividends even within the same treaty.