Letter from the Spanish tax agency (AEAT): what it means, how long you have to reply and what to do in 2026

A letter from the Spanish tax agency (AEAT) is almost always one of three things: a request for documents, a draft assessment or a demand for payment. First identify the type of letter from its heading, then the deadline: a request gives at least 10 working days, objections 10–15 days. An unopened electronic notice counts as served after 10 days, and silence costs a fine from €150.

These letters most often reach people in their first years after moving: when the agency cross-checks a return against bank data, sees foreign accounts through international data exchange, or checks whether someone has become tax resident. Below: how to tell which letter you have, where to find it, how long you have to reply, how to reply online and what happens if you stay silent.

How to tell which letter you received

The type of letter is stated in its Spanish heading. It determines both the deadline and what you need to do. Everyone is required to answer the tax agency’s requests: this is a direct duty under Article 93 of the General Tax Law (LGT).

A reminder letter is not an audit. In its 2026 control plan the agency states plainly that it will keep sending such letters to people who have probably not filed an income tax return and to those whose returns show inconsistencies (AEAT 2026 control plan). It is an invitation to correct things yourself: you then pay a late-filing surcharge instead of a penalty, as explained in our guide to Spanish tax penalties and late returns. If you ignore the reminder, the next letter is usually a request or a draft assessment.

A check of a return comes in two forms. Verificación de datos is a short cross-check: arithmetic, formal errors, mismatches with data the agency has received from banks and employers. Comprobación limitada is broader: the agency examines returns, documents and records and can request information from third parties. Both procedures last no more than 6 months (Article 104 LGT), and after a comprobación limitada the agency cannot reassess the same matter again without new facts (Article 140). A full tax inspection (inspección) runs up to 18 months, or up to 27 for large companies (Article 150).

Regional taxes are a separate case. The property transfer tax (ITP) and inheritance and gift tax are collected not by the AEAT but by the tax office of the autonomous community. A typical letter revalues a purchased flat and asks for a top-up. The logic is the same: read the type of letter and the deadline, and reply on the substance. How the tax is calculated is explained in our guide to property taxes in Spain.

Where the letter is and when it counts as served

The agency sends notices in two ways, and this determines the day the deadline starts.

• A paper letter goes to your tax address (domicilio fiscal). Any adult at the address who gives their name can accept it (Article 111 LGT). If nobody is found twice, the agency publishes a notice in the BOE, and 15 calendar days later the notification counts as served (Article 112). An outdated address in the agency’s records is therefore a risk: deadlines run without you.
• An electronic notice appears in the “Notificaciones” section of the agency’s Sede and in the government’s shared mailbox, DEHú. If it is not opened within 10 calendar days, it counts as received and the procedure moves on (Article 43 of Law 39/2015).

An individual chooses whether to receive letters on paper or electronically (Article 14 of Law 39/2015). Companies (S.L., S.A.) must receive them electronically, as must some autónomos, for example those on the monthly VAT refund scheme (Royal Decree 1363/2010). If you have been enrolled in electronic notifications, the agency tells you so in a separate letter.

An email or SMS alert about a new notice is a courtesy, not a condition: if it never arrives, the notice is still valid (Article 41.6 of Law 39/2015). So check your account yourself at least once a week. For holidays you can request “courtesy days” (días de cortesía): up to 30 days a year without new electronic notices, requested at least 7 calendar days in advance (AEAT on courtesy days). How to log in is covered in our Sede electrónica guide, and how to get a certificate or Cl@ve in our digital certificate guide.

How many days you have to reply

• Request for documents (requerimiento) — at least 10 working days from the day after notification (Articles 55 and 87.4 of the RGAT regulation). Saturdays, Sundays and public holidays do not count. The exact deadline is always written in the letter.
• Objections to a draft assessment (alegaciones) — 10 to 15 days (Article 99.8 LGT).
• Extension. The deadline can be extended by no more than half. You must ask, with a reason, before the last 3 days of the period (Article 91 RGAT).
• Appealing an assessment — 1 month: a recurso de reposición to the same body or a claim (reclamación económico-administrativa) to the TEAR tribunal (Articles 223 and 235 LGT).
• Paying an assessment. If notified between the 1st and the 15th, pay by the 20th of the following month; if between the 16th and the end of the month, by the 5th of the second following month (Article 62.2 LGT).

The agency can review a return for 4 years from the day after the filing deadline (Article 66 LGT). So a letter received in 2026 may well concern 2022 income.

How to reply to a tax agency letter

1. Check that it is genuine. A real letter carries a 16-character CSV code at the bottom. Open the agency’s Sede yourself, not through a link in an email or SMS, and enter the code in the “Cotejo de documentos mediante CSV” service: if the letter is genuine, its PDF opens (CSV verification service). The agency never asks for card numbers, account numbers or passwords by email or SMS (AEAT on phishing).
2. Identify the type of letter and the deadline using the table above. Count the deadline from the day after notification.
3. Gather only what is requested. Extra documents raise new questions. Give a document or explanation for each point of the request.
4. Reply online. In the “Contestar requerimientos o presentar documentación relacionada” section of the Sede you reply using the CSV code from the letter. The taxpayer can do this even without a certificate or Cl@ve; a representative needs an electronic signature. Files up to 128 MB (AEAT instructions). Keep the filing receipt (justificante).
5. Running out of time? Ask for an extension early, not on the last day.

A representative — a gestor, tax adviser or lawyer — can reply on your behalf under a power of attorney registered with the agency (Article 46 LGT). In practice, if a request is unclear, you can book an appointment with the office that sent the letter: its address and phone number are in the letterhead.

What happens if you do not reply

Silence does not stop the procedure. The agency will assess tax on its own data, without your evidence of expenses, deductions and taxes paid abroad, and add a fine for failing to comply with the request (Article 203 LGT):

• €150 for the first unanswered request, €300 for the second, €600 for the third;
• for those carrying on a business (autónomos, companies), where books, invoices or information are not provided: €300 for the first request, €1,500 for the second, and for the third up to 2% of the previous year’s turnover, with a minimum of €10,000.

An example. Through international account data exchange (CRS) the agency sees that a resident holds a brokerage account abroad with €40,000 of dividends missing from the return, and sends a request. If you stay silent, it will assess tax on the savings income scale — €8,280 on €40,000 — and, without your documents, will not credit the tax withheld in the source country. The penalty for underpayment starts at 50% of that amount, i.e. from €4,140, plus interest and €150 for the unanswered request. If you reply on time with documents, the foreign tax is credited under the double taxation treaty, and any penalty that still applies is reduced by 30% for agreement and a further 40% for paying on time — to €1,739 (Article 188 LGT). How to report assets abroad is covered in our Modelo 720 and 721 guide.

If you disagree with the tax agency

• Against a draft assessment you file objections (alegaciones) with documents within the deadline in the letter. This is cheaper and faster than any appeal: the agency often simply recalculates.
• Against a final assessment — a recurso de reposición or a TEAR claim within one month. You choose one route: reposición first and then TEAR, or TEAR directly (AEAT on recurso de reposición, AEAT on TEAR claims).
• A penalty under appeal is suspended automatically, without guarantees (Article 212.3 LGT). The tax itself is suspended only against a deposit, bank guarantee or surety (Article 224).
• Cannot pay at once — you can request a deferral or instalments. They are granted without guarantees if the total debt does not exceed €50,000 (Order HFP/311/2023).

If a debt is not paid on time, an enforcement surcharge is added: 5% if paid before the enforcement order, 10% within the deadline in the order, 20% after that (Article 28 LGT).

Letters newcomers receive most often

Accounts and assets abroad

Spain receives data on residents’ accounts from almost every country under the CRS standard. The 2026 control plan names this data as a source for checks and promises particular attention to people who simulate living abroad to avoid Spanish residence (AEAT 2026 control plan). A typical request asks you to explain income on a foreign account or an unfiled Modelo 720. What to file for accounts, securities and crypto abroad is covered in our guide to Modelo 720 and 721; how taxes apply to substantial wealth in our guide to taxes for wealthy families in Spain.

Tax residence and the Beckham regime

A Spanish tax resident is someone who spends more than 183 days a year in Spain or whose main centre of economic interests is here; if a spouse and minor children live in Spain, residence is presumed (Article 9 of the Personal Income Tax Law). The agency sends requests when someone declares non-residence but the data says otherwise, or checks whether the Beckham regime applied in a given year. How days and the centre of interests are counted: see our guide to Spanish tax residence; the regime’s conditions: see our Beckham Law guide.

A property in Spain

Owners who do not live in Spain receive demands to file Modelo 210 for past years, on imputed income or rental income (details in our non-resident tax guide). Landlords receive objections to their expenses: which costs reduce the tax is decided by documents, not by the figure in the return. If you filed an income tax return with an error, check it before a letter arrives — see our Modelo 100 guide.

Frequently asked questions

How many days do I have to reply to a letter from the Spanish tax agency?

For a request for documents, at least 10 working days from the day after notification; the exact deadline is in the letter. For objections to a draft assessment, 10 to 15 days. A final assessment can be appealed within one month.

What happens if I do not open a tax notice in DEHú?

After 10 calendar days an unopened electronic notice counts as received, and the reply deadline starts running. An email or SMS alert is not required: the notice is valid without it.

What happens if I do not reply to a tax agency request?

The agency will assess tax on its own data, without your evidence of expenses and deductions, and impose a fine: €150 for the first unanswered request, €300 for the second and €600 for the third. For those carrying on a business the fines are higher, up to 2% of turnover.

How can I check that a letter really comes from the tax agency?

Enter the 16-character CSV code at the bottom of the letter in the “Cotejo de documentos mediante CSV” service on the agency’s Sede, opening the site yourself. If the letter is genuine, its PDF opens. The agency does not ask for card details or passwords by email or SMS.

Can I extend the deadline to reply to a tax agency request?

Yes, by no more than half of the period. You must ask with a reason while more than 3 days of the period remain.

What is the difference between a propuesta de liquidación and a liquidación?

A propuesta de liquidación is a draft assessment: you can object within 10 to 15 days, and the agency must consider your objections. A liquidación is the final decision: you pay it on time or appeal within one month.

Do individuals have to receive tax notices electronically?

No, an individual chooses between paper and the government’s electronic mailbox. Companies and some autónomos, for example those on the monthly VAT refund scheme, must receive notices electronically. The agency tells you so in a separate letter.

Key points about Spanish tax agency letters

• The type of letter is in its heading: request, draft assessment, assessment, penalty, enforcement or reminder.
• A request gives at least 10 working days, objections 10–15 days, an appeal one month.
• An unopened electronic notice counts as served after 10 days.
• Silence costs a fine from €150 and an assessment without your documents.
• Check authenticity with the CSV code and reply online with the same code.
• Answer a reminder by correcting your return: you then pay a surcharge, not a penalty.

Sources

• Law 58/2003, General Tax Law — Articles 27, 28, 46, 62, 66, 93, 99, 104, 111, 112, 131–140, 150, 188, 191, 203, 212, 223, 224, 235
• Royal Decree 1065/2007 (RGAT) — Articles 55, 87, 91
• Law 39/2015 — Articles 14, 41, 43
• Royal Decree 1363/2010 — mandatory electronic notifications
• Annual Tax and Customs Control Plan 2026 (BOE 12.03.2026)
• AEAT — replying to requests and submitting documents
• AEAT — verifying a document by CSV code
• Order HFP/311/2023 — instalments without guarantees up to €50,000