Dual Tax Residency in Spain (2026): Living on the Costa, Tax Resident Somewhere Else

Plenty of people on the Costa live here for much of the year and file their taxes somewhere else: in Portugal, the UK, Ireland, Germany or the US. Articles about 2026 warn them that Spain has tightened its residency rules. It has not. The article of the income tax law that decides who is resident in Spain is the same text as in 2006, and the only change this year runs the other way: in June an order took Gibraltar off Spain’s list of non-cooperative jurisdictions, the category that used to be called tax havens.

What has changed is what Hacienda can see and how it reads it. Banks now report accounts every month, a new card return arrives in January 2027, and in July 2026 the Ministry of Finance’s tax directorate adopted a way of counting days that turns a card payment in a Marbella shop into a day in Spain. This guide is for the person with a foot in each country: how Spain decides, what a foreign residence certificate does and does not do, how a tax treaty settles a double claim, the Costa case the Supreme Court decided in 2025, and what it costs to be on the wrong side.

Last verified: 30 September 2026.

What changed in 2026, and what did not

• The law. Article 9 of the income tax law, Ley 35/2006, is original 2006 text. None of the laws that amended the income tax law between 2024 and September 2026 touched it. Orden HAC/649/2026 took Gibraltar off the non-cooperative list from 28 June 2026. Claims of Gibraltar residence raise their own questions, which this guide does not cover.
• Bank data. From January 2026, banks and payment firms report every account on Modelo 196 each month, and the old separate return for non-residents’ accounts has been folded into it. Each holder is identified with the country of residence the bank has on file.
• Card data. Card issuers file Modelo 174 for the first time in January 2027, covering 2026. It gives yearly totals for the cards of people resident in Spain once the charges or the credits reach 25,000 euros. Our guide to what Hacienda sees about cards sets out which cards are in it.
• Property data. Electricity companies already report each supply’s annual consumption with the property’s cadastral reference, on Modelo 159. The tax agency’s 2026 control plan says it will build a consolidated map during 2026 showing how each property was used over a year.
• The day count. In binding ruling V5367-26 of 28 July 2026, the tax directorate adopted the method Spain’s central tax appeals tribunal (the TEAC) set out in 2023. The section on counting days explains it.

The 2026 control plan (BOE-A-2026-5843) keeps its line on simulación de la residencia fiscal fuera del territorio español — faking tax residence outside Spain and adds improper claims under tax treaties. It also still targets people who may owe Spanish tax on their worldwide income but, at best, file as non-residents. It names no country, and it does not single out remote workers or pensioners.

On scale, the only official figure comes from a tool aimed at wealthy people who claim to live abroad. In 2025 it led to 68 million euros of assessments on 145 taxpayers found to be really resident in Spain. There is no published figure for ordinary residents, for the Costa, or for moves to Portugal.

How Spain decides you are resident

You are tax resident in Spain for a calendar year if any one of these applies:

• Days. You spend more than 183 days in Spain in the year. The TEAC puts the threshold at 184 days.
• Economic base. Your main base of activities or economic interests is in Spain, directly or indirectly.
• Family. Your spouse, if you are not legally separated, and your dependent children under 18 live in Spain. The law then presumes you live here too, unless you prove otherwise.

Residence covers the whole calendar year. Spanish law has no split year, and the tax directorate applies treaty tie-breakers to the whole year as well (ruling V2496-25). A UK split year does not carry over. Our guides to the 183-day rule and to leaving Spain cover the year you arrive and the year you go.

The family presumption is the one that catches split households. If one partner registers in Portugal and the other stays in Marbella with the children at school, the law presumes the partner who left still lives in Spain, and it is for that partner to prove otherwise.

The economic test does not count days at all. The TEAC looks at where your income comes from, where your assets are, where they are managed from and where you spend. In a 2016 ruling about someone moving to Portugal while keeping a Spanish employer and a home they owned in Spain, the tax directorate said their centre of economic interests could be considered to be in Spain (V2603-16).

How Hacienda counts your days

The TEAC counts days in three stages, set out in its resolution 00/04045/2020 of 28 March 2023:

• Proven days. Any day with solid evidence that you were in Spain counts in full, however short the visit. The days you arrive and leave both count, whatever time the flight was.
• Presumed days. The days between two proven days count as well, unless you can prove you were outside Spain on them.
• Short absences. Trips away are then added back as if you had stayed, unless you can show you are tax resident in another country.

The tribunal lists the evidence it accepts: card payments in physical shops (online purchases prove nothing about where you were), use of transport, medical visits, notaries, entry to gyms, banks and other premises, motorway tolls paid by Vía-T tag, signed contracts and attendance at courses.

Two examples of the arithmetic. A flight out on Monday evening and back on Friday morning gives Spain two days, Monday and Friday. A card payment in a Fuengirola supermarket on 3 March and another on 20 March, with nothing to show you were anywhere else in between, can put all 18 days on the Spanish side.

The method also works for you. Proof that you were in another country on a given day stops the days around it being presumed Spanish. Our guide to the 183-day rule covers counting in more detail.

What a foreign residence certificate does, and what it does not

A certificate of tax residence from the other country is the document people lean on most, and it does less than they expect.

• Under Spanish law, it does one thing. It stops your short absences being added back to your Spanish days. The tax directorate says it affects only the day test (ruling V2277-16). It does nothing against the economic test or the family presumption.
• It has to match the year. The TEAC treats a treaty certificate for the tax year in question as an essential condition. A certificate saying you are resident now, issued years later, does not prove where you lived in the year Hacienda is asking about.
• In a treaty conflict, it is presumed valid. The Supreme Court held in 2023 (STS 778/2023) that Spanish authorities cannot judge how another country issued a treaty certificate, and that its validity debe ser presumida — must be presumed. It said so again in 2025. The certificate gets you a hearing under the treaty, and the treaty’s own tests then decide.

Ask for a certificate issued for the purposes of the tax treaty with Spain, one for each year.

When two countries claim you

Spain has tax treaties with the UK, Portugal, Ireland, Germany, the Netherlands, France, Switzerland, the US and many other countries. When both countries’ own rules make you resident, the treaty breaks the tie. Each step applies only if the one before does not settle it:

1. Permanent home. You are resident where you have a permanent home available to you.
2. Centre of vital interests. With a home in both countries, you are resident where your personal and economic ties are closer. The Supreme Court calls this wider than Spain’s own economic test.
3. Habitual abode. If that cannot be decided, you are resident where you actually live more.
4. Nationality.
5. Agreement. Failing all of these, the two tax authorities settle it between them.

The first step is the one to think about. A home on the Costa that stays at your disposal is a permanent home in Spain. If you have no home in the other country, the treaty can end there, as the next section shows.

US citizens have one more layer. The Spain-US treaty lets the US tax its citizens as if the treaty did not exist, whichever way the tie-breaker goes.

The Costa case

In July 2025 the Supreme Court decided a residence case from the Costa (STS 971/2025, covering 2014 to 2016). The taxpayer’s position looked strong on paper:

• he held a UK certificate of tax residence for the treaty;
• he produced UK tax returns and certificates of UK tax deducted from his pension;
• he argued that his home was in the UK and the house in San Roque was for holidays.

The Spanish file said otherwise:

• he owned the house in San Roque, his Spanish tax address since 2008;
• he was on the padrón — town-hall register in Estepona from at least 2014;
• he had been registered for public health care as a foreign resident since 2013;
• he had registered cars in Spain at an Estepona address;
• no home in the UK appeared in the file.

The case started in the UK. According to the assessments quoted in the judgment, the UK tax authority passed Spain details of his income because at some point he had told his UK payer that he was tax resident in Spain. The exchange covers people who ask a payer not to deduct tax at source because they live in another country.

The Supreme Court said the tax agency had been wrong to brush aside his UK certificate, and upheld the result anyway. Under the treaty’s first step, the only permanent home on record was in San Roque, so he was resident in Spain. The assessments stood. The High Court of Justice of Andalucía, sitting in Málaga, had already annulled the penalties.

Two things to take from it. The certificate got him into the treaty, and the home he kept on the Costa decided it. And what you tell a payer in one country can reach the tax authority in the other.

Portugal and the NHR certificate

For people claiming residence in Portugal, there is one extra point. The Spain-Portugal treaty’s definition of a resident leaves out people taxed in a country only on income from sources there. The TEAC has held since June 2024, most recently in April 2026, that a person under Portugal’s non-habitual resident (NHR) scheme who is not taxed there on their worldwide income falls within that exclusion. An NHR certificate, in its words, does not open the treaty.

Without the treaty, Spanish law alone decides. If Spain’s own tests make you resident, you are taxed in Spain on your worldwide income, with no tie-breaker to appeal to. If they do not, your Spanish income is taxed as a non-resident’s, without treaty relief. In the April 2026 case the tax agency did not claim the taxpayer was resident. It taxed his roughly 37,900 euros of Spanish pensions as non-resident income and refused the refund he had claimed.

Two limits on this. The Supreme Court has not ruled on the point, and the TEAC’s doctrine binds the tax agency, not the courts. And NHR is closing: Portugal repealed it from 2024, with transitional rules for existing holders and some arrivals up to the end of 2024. Its replacement, known as IFICI, covers employment and business income from listed activities, not pensions, and excludes anyone who has had NHR. Whether IFICI opens the treaty has not been tested.

An ordinary Portuguese treaty certificate, without NHR, works like any other: it gets you to the tie-breaker.

What being wrong costs

Hacienda has four years to assess a year, counted from the day after that year’s filing deadline, and any formal step it takes with your knowledge restarts the count. An inspection normally has 18 months to finish.

The cost depends on who moves first. These figures apply the general tax law to 10,000 euros of income tax left unpaid because no Spanish return was filed. Confirmed September 2026.

Route	Penalty or surcharge	On top
Hacienda finds it	7,500 euros penalty	The tax and late-payment interest
Hacienda finds it, you agree the assessment	5,250 euros penalty	The tax and late-payment interest
Hacienda finds it, you agree and pay promptly	3,150 euros penalty	The tax and late-payment interest
You file first, 18 months late	1,500 euros surcharge, no penalty	The tax, and interest for the months after the twelfth
You file first, pay the tax with the return and the surcharge on time	1,125 euros surcharge, no penalty	The tax, and interest for the months after the twelfth

Where the penalty comes from: not filing counts as concealment, and above 3,000 euros that makes the infringement serious, with a penalty of 50% to 100% of the unpaid tax. The rate rises by up to 25 points for the harm to the Treasury, and when none of the tax was paid the full 25 apply, which gives 75%. Agreeing to the assessment cuts the penalty by 30%, and paying promptly cuts what remains by 40%. Using false documents makes it very serious, at 100% to 150%.

Filing late before Hacienda has contacted you replaces the penalty with a surcharge: 1% plus 1% for each full month late, or 15% after twelve months, with interest from then on. Paying the tax in full with the return, and the surcharge within the period Hacienda gives when it notifies it, cuts the surcharge by 25%.

One more bill if you turn out to be resident. A resident with more than 50,000 euros in any one group of foreign assets (accounts, securities or property) files Modelo 720 by 31 March of the following year. A late one falls under the general fine for late information returns: 20 euros per item of data, between 300 and 20,000 euros, halved if you file before Hacienda asks.

Myths worth dropping

• “Hacienda tracks your phone.” Spain’s data-retention law, Ley 25/2007, releases stored phone data only to authorised officers, with a court order, for serious crime. We found no route for tax checks.
• “Airline records count your days.” Passenger-name records reach the tax agency’s customs surveillance service only to fight terrorism and serious crime, on reasoned requests, and the law bars bulk requests (Ley Orgánica 1/2020).
• “EES tells Hacienda when you come and go.” The EU’s Entry/Exit System has been fully running at the Schengen area’s external borders since 10 April 2026. It registers non-EU nationals on short stays, and does not register EU citizens, holders of a Spanish residence permit or holders of a long-stay visa. The regulation gives access to border, visa and immigration authorities, and to police for terrorism and serious crime. Tax authorities are not on the list.
• “Under 184 days, you are safe.” The economic test and the family presumption do not count days.
• “Declaring yourself non-resident makes you non-resident.” Marking yourself non-resident on the tax census, Modelo 030, is your own statement. It does not decide your residence.

If you think you are on the wrong side

• File before a letter arrives. The table above is the whole argument. Once Hacienda sends a requerimiento — formal request for information about the year, the surcharge route closes.
• Update the census. Modelo 030 records you as resident. Our guide to the domicilio fiscal covers it.
• Claim treaty relief with care. Where the other country taxed the same income as the treaty allows, the treaty gives relief in Spain. Tax the other country did not charge cannot be credited: the tax directorate refused a credit for UK tax relieved by a UK exemption (ruling V0270-23).
• If a letter has already arrived, the deadline is printed on it. Bring in a tax adviser who handles international cases before you reply.

If you mean to stay resident elsewhere, our reading of the tie-breaker is that the file that holds up is the mirror image of the one Hacienda builds: a home you live in there, bank accounts and spending there, health registration there, and a treaty certificate for each year.

Still open in the courts

• The burden of proof. In a judgment of 15 April 2026 the Audiencia Nacional — National High Court said it is for the tax agency to prove Spanish residence. It found the tax agency had shown only 163 proven and presumed days and called the foreign certificate a mere piece of supporting evidence. The case concerned 2011 and can be appealed.
• Three questions for the Supreme Court. In 2026 the court agreed to decide whether either of Spain’s two main tests is enough on its own (January), whether a foreign certificate showing a genuine conflict of residence can rule out penalties (July), and whether Spanish inspectors can declare a certified foreign residence a sham without involving the other country (July).

Any of these could change the picture during 2026 or 2027.

The five-minute version

• Spain’s residency law has not changed since 2006. In 2026 Hacienda gets more data, counts days by a method that favours it, and names improper treaty claims as a target.
• You are resident for a whole calendar year if you spend 184 days or more here, if your main economic base is here, or if your spouse and minor children live here.
• A card payment in a shop, a toll or a doctor’s visit proves a day, and the days between two proven days count too.
• A foreign certificate only stops short trips being added back under Spanish law. In a conflict it gets you to the treaty, where a permanent home on the Costa can decide the case, as it did in the Supreme Court’s 2025 Estepona and San Roque case.
• In the tax agency’s view, a Portuguese NHR certificate does not open the treaty.
• On 10,000 euros of unpaid tax, being found costs a 7,500-euro penalty (3,150 after reductions). Filing first costs a surcharge of up to 1,500 euros and no penalty.

Related guides

• Spain’s 183-Day Rule (2026): What It Means (and What It Doesn’t)
• Tax Residency in Spain: Complete Guide for Expats (2026)
• What Hacienda Sees About Your Cards and Bank Accounts (2026): Modelo 174, 196 and Foreign Cards
• Domicilio Fiscal: The Address Hacienda Actually Writes To, and How to Change It
• Leaving Spain: What You Have to Deregister, and What Happens If You Do Not
• The Year Before Spanish Tax Residency: A Planning Guide

General information, not legal advice, current as of 30 September 2026. Primary sources: Ley 35/2006 (arts. 8, 9, 12 and 13), Ley 58/2003 (arts. 27, 66 to 68, 150, 184, 187, 188, 191 and 198), Real Decreto 1065/2007 (art. 42 bis), Real Decreto 253/2025, Orden HAC/747/2025, Orden HAC/672/2024, Orden HAC/649/2026, Ley 25/2007, Ley Orgánica 1/2020, Regulation (EU) 2017/2226, the tax agency’s 2026 control plan (BOE-A-2026-5843) and its 2025 control results, the Spain-Portugal (1993), Spain-UK (2013) and Spain-US (1990) tax treaties, Supreme Court judgments 778/2023 and 971/2025 and admission orders of 21 January, 2 July and 8 July 2026, the Audiencia Nacional judgment of 15 April 2026 (appeal 1931/2021), TEAC resolutions 00/04045/2020, 00/08325/2022, 00/05948/2021 and 00/05699/2022, tax directorate (DGT) rulings V5367-26, V2277-16, V2603-16, V2496-25 and V0270-23, and Portugal’s CIRS art. 16 and EBF art. 58-A.