Spanish tax inspection: requirements, stages and deadlines

A Spanish tax inspection (the procedure most English sources call a tax audit) is the administrative procedure by which the tax authority checks and investigates whether a taxpayer has complied with their tax obligations and, where it finds non-compliance, regularises their position through one or more assessments. That is the definition in article 145 of Act 58/2003, of 17 December, the General Tax Act (Ley General Tributaria, LGT).

The statute distinguishes two activities that overlap in practice. Verification (comprobación) looks at what you declared: the acts, items and valuations stated in your returns. Investigation looks for what is missing: facts of tax relevance not declared, or declared incorrectly.

Do not confuse a Spanish tax inspection with a routine query from a management office: a letter asking you to support one box of your return does not mean you are under inspection. Read the heading: the notice must state which procedure is being opened and which obligations and periods it covers (art. 87.3 of Royal Decree 1065/2007, RGAT).

Any taxpayer can be inspected, resident in Spain or not, but not for any year and not to any extent. The time limit is the statute of limitations: four years for the authority to assess the debt (art. 66 LGT). The substantive limit is set by the notice of commencement.

That scope is either general or partial. It is partial when it does not cover all the elements of the tax obligation for the period under review; general in every other case. That distinction determines what can be reopened later (art. 148 LGT).

The inspector’s powers are broad: main and auxiliary accounting records, invoices, correspondence of tax relevance, databases and computer files, plus entry onto land and premises (art. 142 LGT).

One boundary is not crossed lightly. Entering a constitutionally protected home requires your consent or a judicial warrant, and the application must state the purpose, necessity and proportionality of the entry (art. 113 LGT). Since Act 11/2021 the warrant can be sought even before the procedure formally opens, provided the entry order identifies the taxpayer and the taxes and periods to be reviewed.

In our view the other limit set by the Supreme Court before that reform still stands: no speculative entries, and none based merely on paying less tax than the sector average (judgment 1231/2020 of 1 October, appeal 2966/2019). Still pending is whether art. 8.6 of the Administrative Courts Act (LJCA) needs the rank of organic law (order of March 2026, ECLI:ES:TS:2026:2623A).

A Spanish tax inspection begins either on the authority’s own initiative or at the taxpayer’s request. The usual route is the first: a notice requiring you to appear and produce documents. From the day after that notice you have a period of not less than 10 days (art. 87.4 RGAT).

It can also start unannounced, with the inspector attending your business, offices or warehouses, where the inspectorate considers it appropriate for the proper conduct of the work (art. 177.2 RGAT).

A point that costs money and is usually discovered too late: returns filed after the inspection has begun, covering the obligations and periods under review, do not produce the effects of arts. 27 and 179.3 LGT (art. 87.5 RGAT). They stop counting as voluntary disclosures, lose the reduced surcharges and do not prevent a penalty. The window to put things right yourself closes when the notice is served. What you can still do is make a payment on account, which stops late-payment interest on that amount from the following day.

If the scope is partial and you would rather close the whole year, you can ask for the inspection to become general. The window is short: 15 days from service of the notice. The authority must then widen the scope or open a general inspection within six months of the request (art. 149 LGT).

1. Commencement. Service of the notice, stating the purpose, the obligations and the periods affected. The maximum period starts running here.
2. Investigation. Appearances, requests and review of documents; the officers decide the place, day and time. The work can take place at your tax domicile, at your representative’s address or office, at your place of business, at the authority’s offices or by videoconference (art. 151.1 LGT).
3. Hearing. The full file is disclosed so you can make submissions and produce evidence before signing the acta. Within the procedure this is the point of no return for evidence: afterwards no further documents may be added unless you prove they could not have been produced earlier (art. 96.4 RGAT). In a later claim the Supreme Court accepts evidence not produced earlier, unless the taxpayer acted abusively or in bad faith (judgment 1362/2018 of 10 September, appeal 1246/2017), but it is unwise to rely on that route.
4. Signature of the acta. The document recording the proposed adjustment, classified as con acuerdo (by agreement), de conformidad (agreed) or de disconformidad (contested).
5. Assessment. The act that fixes the final amount and closes the procedure. It can be challenged by recurso de reposición or an economic-administrative claim, within one month.

A Spanish tax inspection must conclude within 18 months as a general rule, or 27 where one of the three cases in art. 150.1(b) LGT applies. Time runs from service of the notice of commencement until service of the assessment, and it is a single period covering every obligation and period under review. One proven attempt to serve the full text of the decision is enough (art. 150.2 LGT).

The third ground for 27 months is new: added by the sixth final provision of Act 7/2024, of 20 December, with effect for tax periods beginning on or after 31 December 2023.

The 60 days are the most underused tool in the procedure. You apply to the acting office at least seven calendar days in advance, you must justify the circumstances, and a refusal cannot be appealed (art. 184 RGAT). While they run, the time to answer requests is suspended, and they extend the maximum period rather than eating into it. If you have to gather documents in another country, they are usually the best way to buy time.

The acta is a proposal, not the assessment. Its class governs what happens next and, above all, how much of the penalty reduction you keep.

A further 40% reduction applies to what is left after the agreement reduction, provided the penalty is paid within the voluntary period of art. 62.2 LGT (or under a deferral secured by bank guarantee or surety insurance) and neither the assessment nor the penalty is appealed (art. 188.3 LGT). A 10,000 euro penalty therefore falls to 7,000 and, with prompt payment, to 4,200: an effective cut of 58%. This second reduction does not apply to actas by agreement. Refusing to sign is not neutral: the acta is then processed as contested.

No. Missing the deadline does not cause the procedure to lapse; it carries on to its conclusion (art. 150.6 LGT). But it produces three effects that, argued properly, change the financial outcome:

• The limitation period is not treated as interrupted by the work carried out within the period that was missed. In long files, that can leave the oldest year time-barred.
• Payments made between commencement and the first action taken after the deadline was missed become voluntary for the purposes of art. 27 LGT.
• No late-payment interest is charged from the moment of the breach until the procedure ends.

Track the calendar from day one. The mistakes we see most often: producing documents after the third request has expired, which triggers the three-month extension; signing an agreed acta without reading its legal reasoning; and letting the hearing stage pass without submissions.

If you do not live in Spain, a Spanish tax inspection follows the same procedure, but the logistics and the service of documents change. Whether you must appoint a representative depends on where you live. Art. 10 of the consolidated Non-Resident Income Tax Act (IRNR, Royal Legislative Decree 5/2004) only binds taxpayers who are not resident in another EU Member State (the European Economic Area is treated alike if mutual assistance is in place), and only in these cases: a permanent establishment; the cases in its arts. 24.2 and 38; or a request from the authority because of the amount and nature of the income or because you own property in Spain.

A resident of the UK, the US or Switzerland who owns a flat here can receive that request. It also binds residents of territories with no effective exchange of information who hold assets or rights in Spain. The appointment must be notified within two months. Failing to do so is a serious tax infringement, fined 2,000 euros, rising to 6,000 in those territories.

Your Spanish tax domicile is set by art. 11 IRNR: the place of effective management where there is a permanent establishment; the representative’s address or, failing that, the location of the property, where the income is from real estate; and in other cases, the representative’s address or, failing that, that of the jointly liable party. That is where notices are served, and where most files go wrong: the taxpayer finds out once the deadline for submissions has expired.

A practical point that saves plane tickets: proceedings may be conducted by videoconference or equivalent digital systems, with secure document transmission. The authority decides, and the taxpayer must consent (art. 99.9 LGT, read with art. 151.1(e)). The file is handled in Spanish (art. 15.1 of Act 39/2015).

On real exposure, the guidelines of the 2026 Annual Tax and Customs Control Plan, approved by Resolution of 11 March 2026, expressly mention the simulation of tax residence outside Spain and the improper use of double tax treaties, and they draw on automatic exchanges of financial account information (CRS), country-by-country reporting and the administrative cooperation directives (DAC). Check your calendar too: modelo 210 filing deadlines have changed for accruals from 2026 onwards (Order HAC/623/2026, AEAT).

Start by pinning down the date of service: the minimum 10 days in the notice of commencement, the 15 days to request a general inspection and the 18 or 27 months of the procedure all hang on it. What the AEAT is after depends on your profile:

1. Check what you have received. Which procedure it is, where it was served and when. If the letter reached your Spanish home or your representative, time may already be running.
2. Appoint someone to act for you. To appeal, accept obligations or sign on your behalf, representation must be proved by a legally valid means or on the AEAT’s standard forms (art. 46.2 LGT).
3. Do not file returns on your own. Once the inspection has begun they do not prevent a penalty. Define the scope first.
4. Gather proof of residence. Start with a tax residence certificate from the other State: if you prove residence there, occasional absences stop counting towards the 183 days (art. 9.1(a) LIRPF).
5. Update your address. A change of tax domicile has no effect against the AEAT until it is notified (art. 48.3 LGT).
6. Settle your strategy before the acta. If another State already taxes that income, weigh the treaty’s mutual agreement procedure (Royal Decree 1794/2008) alongside your appeal options.

At Martínez-Cardós Abogados we represent non-residents through a Spanish tax inspection in English or Spanish, without them having to travel to Spain. If you have received a notice of commencement, write to us before you respond or see our tax advice for non-residents.

How many years back can the Spanish tax authority go? Four years, the limitation period for the authority’s right to assess, running from the day after the filing deadline for the return. With two qualifications: limitation does not bar verification and investigation under art. 115, and the right to review carried-forward losses, credits and deductions runs for ten years.

Can I refuse to let an inspector into my home? Yes, where it is a constitutionally protected dwelling: the authority needs your consent or a judicial warrant, and the application must state purpose, necessity and proportionality. Entry onto land and business premises needs no warrant, but it does need an entry order from the administrative authority, unless you consent to the access.

What happens if I ignore the notice of commencement? The procedure continues without you. Non-appearance does not stop it, may amount to an infringement for obstruction, and makes it easier for the authority to use the indirect assessment method. You also lose control over the facts recorded in the acta.

Is signing an agreed acta always the cheapest option? Not always. It cuts the penalty by 30%, plus 40% more if you pay within the voluntary period and do not appeal, but you accept the facts in the acta. Where the dispute is about legal characterisation and there is favourable authority, contesting can work out better.

I am a non-resident and the notice went to my Spanish representative. Is that valid? Yes. If you were required to appoint a representative and did so, service at their address is fully effective (art. 110.2 LGT). Hence the importance of keeping the appointment current and agreeing an immediate-alert protocol with them.

Do I have to travel to Spain for a tax inspection? No. You can appear through a representative (art. 142.3 LGT), and the work can take place at their office (art. 151.1(a) LGT) or by videoconference.

What if the AEAT cannot find me because I live abroad? After two failed attempts it publishes a notice in the Official State Gazette (BOE) and you have 15 calendar days to appear; if you do not, you are deemed served and the procedure goes on (art. 112 LGT). That route can be challenged where the authority did not take the care required: in 2025 the High Court of Murcia ordered a claim rejected as late to be admitted because correct addresses were already on file (ECLI:ES:TSJMU:2025:1473).

Can the AEAT collect from me if I live in another country? Yes. It can seize what you own in Spain and ask other States for mutual assistance in recovery (art. 177 bis LGT).

How much longer than 18 months can a Spanish tax inspection run? Up to 60 calendar days more if you request them, three or six months for late production of documents, plus however long the suspension grounds in art. 150.3 LGT last. Justified interruptions and delays not attributable to the authority no longer come off the clock.

A Spanish tax inspection has rules, and those rules protect the taxpayer too: a defined scope, a file that must be disclosed, a deadline with consequences if missed, and actas with very different financial effects. The gap between a well-run file and a badly run one is rarely about the substance. It is about the calendar and the moment evidence goes in. If you live abroad there is one more risk: finding out too late.

If you have received notice of the commencement of a Spanish tax inspection, or if you reside outside Spain and have income or property here, we recommend contacting us before responding to the first request from the tax authorities. At Martínez-Cardós Abogados we have over 40 years of experience managing and handling tax inspections, ensuring that the Tax Administration acts within the limits of the law. We review the scope of the inspection, the calculation of applicable time limits, and the strategy for agreeing with or contesting its findings. This article is general information and does not replace a review of your file.

María Purificación Martínez-Cardós Ruiz