Before you start

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Padrón registration in Gipuzkoa, which is what establishes foral residence
Records of worldwide income and foreign assets
Credentials for the Gipuzkoa foral electronic office, which are separate from state Cl@ve

Step-by-step

1
Understand which authority you belong to
Foral residence follows where you habitually live, established through the padrón. Living in Donostia makes you a Gipuzkoa taxpayer. Living forty minutes away in Navarre puts you under Navarre's own separate foral regime, and in Cantabria under the Spanish state system. The boundaries are real and administrative, not notional.
OnlineWho: You
2
Get credentials for the Gipuzkoa electronic office
The foral treasury runs its own online system with its own identification. State Cl@ve credentials do not get you into it. Set this up early — it is where your return, your notifications and your payment references all live.
OnlineWho: You
3
Find an asesor who works with the Hacienda Foral de Gipuzkoa
Ask the question directly and treat a vague answer as a no. Note that 'Basque' is not specific enough: Álava, Bizkaia and Gipuzkoa legislate independently and their rules differ from each other. A first filing made on the wrong basis is difficult to unwind.
In personWho: You
4
Establish your tax residence position for the year
The 183-day test and the centre-of-economic-interests test work broadly as in the rest of Spain, and Spanish tax residence is worldwide. What differs is which authority then assesses you. If you arrive mid-year with substantial foreign income, take advice on the timing before rather than after.
In personWho: You
5
Check the foral wealth tax position, which is a different tax
Gipuzkoa levies an Impuesto sobre la Riqueza y las Grandes Fortunas — its own design, its own thresholds and its own reliefs — rather than the state's Impuesto sobre el Patrimonio. It also enacted its own solidarity tax on large fortunes by Norma Foral 3/2023. Nothing you have read about Madrid rebating wealth tax, or about the Valencian or Balearic thresholds, describes your position.
In personWho: You
6
File the foral annual return in its own window
Gipuzkoa runs its own filing campaign with its own dates, its own pre-filled proposal and its own appointment system. The deadlines do not necessarily match the state's April-to-June Renta window. Check the foral calendar rather than the national one.
OnlineWho: You

Documents you’ll need

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Gipuzkoa foral electronic office credentials
Padrón certificate establishing foral residence
Employment income certificates from Basque employers
Records of all worldwide income, foreign accounts, property and securities

Things most newcomers don’t know

You do not file with the Agencia Tributaria, and almost no general guidance says so.

The Concierto Económico gives the Basque provinces the power to set and collect income, corporate, wealth and inheritance taxes themselves. Every article about Spanish tax residency, the Beckham Law, the Modelo 720 or the Renta window is describing the state system. In Donostia you are dealing with the Diputación Foral de Gipuzkoa — different rates, deductions, forms, platform and calendar. This is the defining administrative fact of living here and it is systematically absent from relocation content.

Source: Diputación Foral de Gipuzkoa

The wealth tax here is not the Spanish wealth tax — it is a different instrument.

Where the rest of Spain has the Impuesto sobre el Patrimonio, with regions rebating or raising the exempt minimum, Gipuzkoa levies its own Impuesto sobre la Riqueza y las Grandes Fortunas with its own design, and enacted its own version of the temporary solidarity tax on large fortunes by Norma Foral 3/2023. Comparisons of Spanish regions on wealth tax simply do not include this. If assets are a material part of your decision, get the foral position from a Gipuzkoan adviser before comparing anything.

Source: Diputación Foral de Gipuzkoa

The three Basque provinces are not one tax system.

Álava, Bizkaia and Gipuzkoa each legislate their own Normas Forales. Rates, deductions and thresholds differ between them, and an adviser in Bilbao is working from Bizkaia's rules. For someone weighing Donostia against Bilbao or Vitoria, that is a genuine variable rather than a technicality — and it is one more reason 'Basque tax advice' is not a sufficient specification.

Source: Diputación Foral de Gipuzkoa

The impatriate and nomad regimes you have read about are state regimes.

The Beckham Law and the digital nomad tax treatment were created in state legislation and are administered by the Agencia Tributaria. How, and whether, an equivalent applies to a Gipuzkoa taxpayer is a separate question with its own answer, and it is not safe to assume the state position carries over. If your move is planned around one of these regimes, establish the foral position before committing to living on this side of the boundary.

Source: community-reported

Common mistakes to avoid

Filing with, or planning around, the Agencia Tributaria when you are a Gipuzkoa taxpayer.
Hiring a tax adviser who works with the state system, or with Bizkaia's rather than Gipuzkoa's.
Assuming the state Renta window and deadlines apply to your foral return.
Assuming state-level impatriate or nomad tax regimes carry over unchanged.
Comparing Spanish regional wealth tax thresholds as though Gipuzkoa were on the same instrument. It is not.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.

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