First IRS Tax Return in Portugal: A New Resident's Checklist

Do not wait until April to prepare your first Portuguese IRS return. (IRS here is Portugal’s personal income tax, not the US agency.) Under the standing rule, the return is filed online from 1 April to 30 June, and 30 June does not move for weekends or holidays. Before then, sort out your access to Portal das Finanças, the portal of the Autoridade Tributária e Aduaneira (the tax authority, or AT), along with your tax address, your invoices and, if you choose to communicate it, your household.

On our reading of AT’s 2026 campaign conditions for 2025 income, someone did not meet every condition for IRS Automático, the automatic return, if they were resident in Portugal for only part of the year, had any foreign income, held RNH (non-habitual resident) status or had a deduction for international double taxation. A taxpayer who does not meet all the conditions files Modelo 3 (the return you complete yourself) under the general rules, unless exempt from filing under Article 58 of the IRS Code. That is a reading of AT’s list for one finished campaign. It is not a ruling on your case, a view on your residence or a statement about a later campaign.

Portugal’s 2026 campaign, covering 2025 income, is finished. No 2027 campaign calendar was found in AT’s published materials when we checked on 20 September 2026. The standing dates below apply unless amended, so check AT’s new campaign material before filing.

What should you prepare, and when?

This is the first-return checklist in calendar order. Each date is labelled as a standing rule or as a record of the 2026 campaign.

Step	What to check	Date and label
1	Make sure Portal das Finanças access works for everyone whose authentication you will need	Before the campaign
2	Check that AT records you as resident at your Portuguese address	Within 60 days of a change of residence status — standing rule
3	Confirm your invoices and, if you want the automatic provisional return to reflect it, communicate your household (optional)	By the end of February — standing rule. 2026 campaign record (2025 income): 2 March 2026, only because the last day of February was a non-working day
4	Review AT’s deductible-expense figures and complain if necessary	16–31 March 2026 — 2026 campaign record (2025 income). Standing rule: the buyer may complain about invoice figures until 31 March
5	Confirm IRS Automático or file Modelo 3 with the right annexes — the conditions, and the Article 58 exemption from filing, are under “Should you confirm IRS Automático or file Modelo 3?“	1 April–30 June, and 30 June does not move for weekends or holidays — standing rule. The IRS Automático conditions are 2026 campaign wording (2025 income)
6	If married or in a de facto union, decide between separate and joint taxation — the conditions are under “Should you file jointly or separately?”	In the return — standing rule
7	If you want a refund by bank transfer, enter an IBAN that belongs to at least one taxpayer the return covers, and note the assessment and payment dates	When filing; the IBAN rule is from the Modelo 3 front-page instructions as served on 20 September 2026. 2026 campaign record (2025 income): any refund or payment by 31 August 2026 for returns filed on time
8	Check the triggers for qualified help under “When do you legally need a certified accountant?”	Before you submit

AT’s leaflet of main dates for the 2026 campaign records the dates for 2025 income. It is the record of a finished campaign, not a 2027 calendar.

Which February and March jobs come before the return?

Under the standing rule, the legal date for confirming invoices and communicating the household is the end of February. In the 2026 campaign (2025 income) it moved to 2 March 2026 only because the last day of February was a non-working day. Do not assume that the same adjusted date will apply in another campaign.

Do you have to communicate your household?

Communicating your household is optional: the law says taxpayers “may” do it, and the rule exists for the purposes of the automatic provisional return (standing rule). If you do it, the details describe your household on the last day of the tax year, and every household member must authenticate.

For a first-time filer, the fallback matters. If nothing is communicated and there is no previous return, the automatic provisional return treats the taxpayer as not married, not in a de facto union and without dependants. That standing rule is in Article 58-A of the IRS Code.

What should you check on your invoices and expenses?

Under the standing rule, invoices count for the year they were issued. If you want the deduction, you must ask the issuer to put your NIF on the invoice. An invoice issued without it can still be communicated using its QR code or unique document code.

The buyer may complain about invoice figures until 31 March — a standing rule, set out with the others in Article 78-B of the IRS Code. In the 2026 campaign (2025 income), AT’s leaflet set 16 to 31 March 2026 for reviewing deductible expenses and complaining.

The same 2026 campaign leaflet (2025 income) let a taxpayer, instead of using AT’s figures, declare health, training and education, property and care-home expenses in table 6C1 of Annex H. That choice applies to all of those expense classes and to every household member, and you must be able to prove the amounts. A complaint does not suspend the filing or payment deadlines.

Can you get into Portal das Finanças?

AT’s portal-access leaflet, as we read it on 20 September 2026, is current AT guidance, not a standing legal rule or a promise about a later campaign. It gives two ways into Portal das Finanças:

• Autenticação.gov, using a Cartão de Cidadão (the Portuguese Citizen Card) or Chave Móvel Digital (the Digital Mobile Key).
• Your NIF and a Portal das Finanças password.

If you register with your NIF to get a password, the leaflet says AT sends it only by post and only to the address in its records, not by email or to another address. The same leaflet, as checked on 20 September 2026, gives an average wait of 5 working days.

Where AT’s record shows a fiscal representative’s address, the leaflet says the letter goes there. The leaflet gives no time for addresses abroad, so we cannot give you one either. The details are in AT’s Portal access and passwords leaflet.

In the same leaflet, registration through Cartão de Cidadão or Chave Móvel Digital posts no password: you set one yourself. On Autenticação.gov’s pages, checked 20 September 2026, a foreign person’s Chave Móvel Digital is linked to a passport, residence permit or residence card, and activating it with a residence permit, or a residence card or certificate, requires your tax number. We did not examine every activation route.

Within IRS Automático, in AT’s 2026 campaign wording, a couple gets the joint return and the two separate returns only when each partner authenticates with their own password, and each dependant authenticates with their own password. We do not claim the same workflow for someone filing Modelo 3.

Does AT know that you are resident?

Under the standing rule in Article 19 of the General Tax Law, a change of residence status must be reported to AT within 60 days, and a change of domicile has no effect until it has been communicated.

For a foreign national with a foreign address on AT’s record who is changing from non-resident to resident, the ordinary online address form does not apply, as AT’s leaflet on foreign citizens’ tax address explains. As AT’s guidance stood on 20 September 2026, that change goes through e-balcão (AT’s online counter) or in person, following AT’s non-resident-to-resident instructions.

We cannot tell you whether or when you became tax resident. The tests are in Article 16 of the IRS Code, and applying them to your facts is a question for AT or a qualified professional.

A fiscal representative is a separate issue. Under the standing rule in Article 130 of the IRS Code, non-residents with income subject to IRS, and residents absent from Portugal for more than six months, must appoint a representative resident or based in Portugal, unless they join one of the electronic notification channels named in Article 19 of the General Tax Law. It is optional in EU and EEA cases. Our NIF guide, linked at the end, explains the fiscal-representative rules, so we do not repeat them here.

Should you confirm IRS Automático or file Modelo 3?

Check AT’s conditions before you choose a route. The conditions and the portal steps in this table are AT’s 2026 campaign wording (2025 income), not a promise about 2027; the 1 April to 30 June window is a standing rule.

Route	When it fits	What you do
IRS Automático	You meet every condition AT publishes and the provisional return matches your real situation	Review it and confirm it between 1 April and 30 June
Modelo 3	You do not meet all the conditions, or the provisional return does not match your real situation, and you are not exempt from filing under Article 58	In AT’s 2026 campaign wording (2025 income): go to IRS > Entregar Declaração and fill the return in yourself, optionally pre-filled with AT’s data
Exempt from filing	You fit an exemption in Article 58 (one common exemption is described below)	No return is required, although an exempt person may still file

In AT’s 2026 campaign wording (2025 income), IRS Automático is a pre-filled provisional return that becomes final when you confirm it within 1 April to 30 June.

Separately, a standing rule covers what happens if you do nothing. If a taxpayer who is not exempt from filing neither confirms the provisional return nor files any other return by the end of the window, AT converts the provisional return to a final one, and couples are then taxed separately. A replacement return may be filed within 30 days after the assessment without penalty.

Article 58-A does not cover holders of the assets identified in Article 57(7). These standing rules are in Article 58-A of the IRS Code.

AT’s IRS Automático page sets out a longer cumulative list of 2026 campaign conditions. Four that a newcomer meets first were:

• income obtained only in Portugal;
• resident in Portugal for the whole year;
• no RNH status;
• no deduction for international double taxation.

Those four are examples, not the complete list, so read AT’s page in full before you confirm anything.

AT’s 2026 campaign page does not say how IFICI holders sit in its list, and we will not guess. If you hold IFICI, put that question to AT, and see our NHR and IFICI guide, also linked at the end, for the regime itself.

When do you file Modelo 3?

Under the standing rule, the return is filed online from 1 April to 30 June, and 30 June does not move for weekends or holidays. It covers the previous year’s income.

An extension to 31 December exists only where all three of these conditions apply (standing rule):

1. The taxpayer has foreign-source income with a right to a credit for international double taxation.
2. The amount is not yet determined in the source state by 30 June.
3. The taxpayer tells AT inside the 1 April to 30 June window that the conditions are met, naming the income type and the source state.

That extension is set out in Article 60 of the IRS Code. Whether you personally qualify is a cross-border tax question we do not answer, and a sound reason to get qualified help before 30 June.

Do you need two returns if your residence status changed during the year?

You may. Under the standing rule in Article 57 of the IRS Code, a taxpayer with two residence statuses in Portugal in the same year — resident and non-resident — owes one return for each status, subject to the general exemptions.

The Modelo 3 front page that AT served on 20 September 2026 is a PDF headed as in force from January 2025, so check for a newer version before you file. On that version, Quadro 8C (table 8C) gives the period covered by the residence status marked in Quadro 8A or 8B, and the front-page instructions repeat the two-return rule.

Residence can start on the first day of the stay, which is why an arrival year can be a part-year. “Can” is deliberate: Article 16 sets the tests and their exceptions, and we make no residency determination here.

Could you be exempt from filing?

Article 58 contains several exemptions, and we cover only one. It is a common one. Under the standing rule (amounts as published, checked 20 September 2026), it covers someone whose only income is:

• employment or pension income totalling €8,500 or less with no withholding; and/or
• income taxed at the Article 71 flat rates that is not aggregated.

That exemption does not apply if you opt for joint taxation, receive income in kind, receive certain annuities, receive alimony above €4,104, or hold the assets identified in Article 57(7). An exempt person may still file.

The other exemptions in Article 58 of the IRS Code are outside this article. We did not capture whether foreign-source income counts towards the €8,500 route; that is a question for AT. Do not assume that a low income means no return.

Which annexes should a newcomer check?

The annex depends on the income, the accounts and any registered tax regime involved. We cannot select the annexes for an individual return. This section covers two, Annex J and Annex L; Annex C comes up later, with the accountant rule.

Who files Annex J?

Under the 2026 campaign form (2025 income), residents file Annex J when they or a household dependant:

• had income from outside Portugal; or
• hold, benefit from or may sign on deposit or securities accounts at a non-resident financial institution, or at a foreign branch of a resident one.

On the same 2026 campaign form, the annex is individual: one per person who holds the foreign income or the accounts as holder, beneficiary or authorised signatory. That form identifies foreign accounts in Quadro 11 by IBAN and BIC, or by account number where those do not exist.

Its instructions also say original foreign income and tax documents must be kept so that you can supply them if AT asks. The precise wording is in the 2026 Annex J form.

Who files Annex L?

Under the Annex L instructions AT served on 20 September 2026 (a PDF headed January 2025), Annex L is filed by an income holder registered for tax purposes as either:

• a non-habitual resident (RNH); or
• a beneficiary of IFICI, the scientific research and innovation incentive.

The trigger is registration under the regime, not a personal belief that you qualify. Those Annex L instructions separate RNH from IFICI on the form. Eligibility is outside this article; our IFICI guide explains the regime.

Should you file jointly or separately?

Under the standing rules in Article 13 and Article 59 of the IRS Code, separate taxation is the default. The joint option must be exercised by both spouses or de facto partners in the return, and it is valid only for that year.

Under separate taxation, each spouse or partner, unless exempt from filing, declares their own income and 50% of the income of the dependants in the household. Choosing joint taxation also removes the Article 58 filing exemption. Where the conversion rule under “Should you confirm IRS Automático or file Modelo 3?” applies, with the conditions stated there, couples are taxed separately.

In AT’s 2026 campaign wording (2025 income), the automatic return shows a provisional assessment for each regime, separate and joint. That depends on the authentication conditions set out under “Can you get into Portal das Finanças?”: each partner, and each dependant, authenticates with their own password. Which one costs less is a personal calculation we do not make, and we do not promise the same comparison to someone filing Modelo 3.

When does AT assess the return, and when is any refund or payment due?

Under the standing rules, the dates depend on whether a return was filed in the standard window:

Event	Standing rule: date and condition
AT assessment	By 31 July, for a return filed in the standard 1 April to 30 June window
Payment, if tax is due	By 31 August, where the assessment was made by that 31 July date
Refund, if one is due	By the end of the applicable payment deadline
Assessment where no return was filed	By 30 November
Payment in that no-return case	By 31 December, where the assessment was made by that 30 November date

The dates come from Article 77, Article 97 and Article 96 of the IRS Code. The law sets an outer deadline for a refund and promises no number of days, so do not plan around any claim that refunds arrive within a fixed period.

We did not capture the assessment timing for a return that uses the extension to 31 December.

For a refund by bank transfer, the IBAN must belong to at least one taxpayer the return covers, under the Modelo 3 front-page instructions as served on 20 September 2026. We did not capture whether a non-Portuguese IBAN is accepted; that is a question for AT. If you are still deciding whether to open a local account, our bank-account guide, linked at the end, covers a Portuguese bank account and IBAN.

What happens if you file late?

Under the standing rule, where a return was required — the taxpayer had a filing obligation and was not exempt from filing under Article 58 of the IRS Code — a missing or late return carries a fine of €150 to €3,750 (amounts as published, checked 20 September 2026). That is the statutory range, not a prediction of what anyone will pay.

The fine falls to 12.5% of the legal minimum if the taxpayer:

• asks to pay before an auto de notícia (a formal offence report) has been drawn up, a report or complaint received, or a tax-inspection procedure begun;
• pays within 30 days of notification of the reduced fine; and
• puts the matter right in that time.

No fine applies to someone with no tax conviction, waiver or reduction in the previous five years. A separate waiver exists where there is no actual revenue loss: it must be requested, and the fault put right, within the period given for the defence.

The fine range is in Article 116 of the RGIT, the general tax-offences law, with the reduction and waiver conditions in Article 30 and Article 29 of the same law. Every one of these rules is conditional, and we cannot predict a fine for any reader.

When do you legally need a certified accountant?

A certified accountant is a legal requirement where you have Category B (business and professional) income under organised accounting. That income is declared in Annex C, and the 2026 campaign Annex C instructions (2025 income) require the certified accountant’s NIF.

Organised accounting is required for Category B holders outside the simplified regime. Under the standing rule (amount as published, checked 20 September 2026), the simplified regime covers those who did not exceed €200,000 gross Category B income in the previous period. They may still opt for organised accounts.

The simplified regime ends, from the following period, only after:

• two consecutive periods over the limit; or
• one period over it by more than 25%.

In the start-up year, the estimated annual income in the start-of-activity declaration decides. The rules are in Article 28 and Article 117 of the IRS Code. The accountants’ statute, in the 2024 edition published by their professional body, reserves to certified accountants the signing of tax returns based on accounting information for those who have, or should have, organised accounting.

For other income types we found no official rule requiring an accountant. That is not proof that none exists.

Even where one is not legally required, qualified help is sensible if you have:

• foreign income or foreign accounts that call for Annex J;
• a possible foreign-tax-credit extension;
• two residence statuses in the same year;
• registered RNH or IFICI status;
• a choice to make between joint and separate taxation;
• Category B income near the organised-accounting limit; or
• a late or missed return, where a return was required.

Each trigger is tied to a rule above and can make qualified help sensible. We name no adviser and recommend none.

What should you do next?

• Check the fiscal-representative rules. We only summarise them here; our NIF guide covers the NIF, the fiscal representative and electronic notifications.
• Confirm any special tax registration. If you hold RNH or IFICI, read how NHR and IFICI work before you look at Annex L.
• Think about the refund IBAN. If a refund is due and you want it by bank transfer, our guide to opening a Portuguese bank account covers a Portuguese account and IBAN. We did not capture whether AT accepts a non-Portuguese IBAN.
• Keep the wider budget in view. For general household-budget context, see our cost of living in Portugal guide.
• Recheck AT’s campaign material. No 2027 campaign calendar was found in AT’s published materials when we checked on 20 September 2026, so look at AT’s leaflets index for a new calendar before you act.

This is general information, not personal tax, legal or cross-border advice, and it makes no residency determination. Confirm your filing position with the Autoridade Tributária e Aduaneira or a qualified Portuguese tax professional, above all if any trigger under “When do you legally need a certified accountant?” applies to you.