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2026 at a glanceFebruary and MarchApril to June: filing windowJuly to August: assessment and paymentIMI and other deadlinesCommon questions2026 at a glance
Portugal's tax year is the calendar year, and the return you file in 2026 covers income earned in 2025. The cycle runs: housekeeping deadlines in late winter, the filing window in spring, assessment and payment in summer, and property tax instalments through the year. Miss the early deadlines and you lose deductions; miss the filing window and you collect penalties even if no tax was due.
A calendar with separate lanes
Use the dated sections below for the actual deadlines. These are different workstreams, not one deadline shared by every taxpayer.
- PrepareHousehold details, invoice review and supporting records.
- File and follow upReturn, assessment and any payment or refund.
- Other obligationsKeep property and activity-related obligations on their own schedule.
| Date | What is due |
|---|---|
| 2 March 2026 | Validate invoices in e-Fatura and confirm your household composition (the usual end of February deadline moved because it fell on a weekend; the legal deadline is normally the end of February; in 2026 it moved to the next working day because month-end fell on a weekend) |
| March 2026 | Short window to check and dispute the deduction totals the tax office computed from your invoices (confirm the exact dates for the year) |
| 1 April to 30 June 2026 | Modelo 3 filing window, the same for every income type |
| 31 July 2026 | Target date for the tax office to issue assessment notes on returns filed on time |
| 31 August 2026 | Deadline to pay any balance due, and the usual outer date for refunds |
| May, August, November | IMI property tax instalments, depending on the amount |
February and March
Two things happen before the filing season opens, and both feed directly into your assessment. First, your household composition must be confirmed on the Portal das Finanças, the tax authority's online portal. Births, marriages, divorces, a dependent moving out, a change of fiscal address: all of it has to be communicated by the deadline, which in 2026 was 2 March. The household on file determines dependents' deductions and whether joint taxation is available.
Second, the invoices that accumulated against your NIF (your Portuguese tax number) through 2025 must be validated in e-Fatura by the same date. Invoices the system could not classify sit in a pending queue, and unclassified invoices earn no deduction. The e-Fatura guide covers the validation in detail.
April to June: filing window
The Modelo 3, the annual return, is filed between 1 April and 30 June. The window is the same whether you earn salary, freelance income, pensions, or investment income, and whether you file the pre-filled automatic return or build the declaration annex by annex. A conditional extension can apply when qualifying foreign income gives entitlement to a foreign tax credit and the source-country tax amount is not determined by the normal deadline. Article 60(3)–(4) sets a 31 December deadline when its conditions and timely communication requirement are met. Check article 60. Foreign income alone does not grant an extension.
Filing in the last days of June means discovering a missing document with no room to fix it calmly. If this is your first return, the first Modelo 3 guide walks through the portal.
July to August: assessment and payment
After submission the tax office validates the return and issues the assessment note (nota de liquidação). For returns filed inside the window, the stated target is 31 July 2026. Refunds are paid to the IBAN registered on the portal. Check the campaign’s published assessment and refund dates. If the assessment shows a balance due, payment is due by 31 August 2026. The payment reference arrives with the assessment note, and paying late adds interest on top of the tax.
IMI and other deadlines
If you own property, IMI, the annual municipal property tax, arrives separately from income tax. The bill is charged on the previous year's ownership and is split by amount: small bills are paid in one instalment in May, mid-sized bills in two instalments in May and November, and larger bills in three instalments in May, August, and November. The thresholds that decide the split have been stable for years (around one hundred euros for a single payment and five hundred for three instalments), but confirm the current figures on your IMI note itself.
Worked example
Rui's annual IMI note for his Porto flat comes to 240.00, using a round figure for illustration.
A bill sitting between the single-payment and three-instalment thresholds splits into two equal instalments; the exact thresholds and references are printed on the IMI note itself.
Freelancers carry extra dates through the year: quarterly VAT returns and monthly or quarterly social security declarations run on their own calendar, covered in the recibos verdes guide.
Common mistakes
- Waiting for a reminder. Validation and review deadlines may pass without a personal reminder; put the dates from the applicable annual calendar in your own diary.
- Filing in the last days of June. Discovering a missing document with no room left to fix it is avoidable.
- Going quiet after missing 30 June. A voluntary late return within 30 days sits at the bottom of the penalty scale; waiting for the tax office to notice costs more.
- Paying after 31 August. Late payment adds interest on top of the tax; the payment reference arrives with the assessment note, so use it as soon as it lands.
- Expecting an expat extension. Foreign income alone does not create an extension. Check the conditional foreign-tax-credit extension and timely notification requirements in article 60(3)–(4).
Common questions
What happens if I miss the 30 June deadline?
File anyway, as soon as possible. Late filing brings a fine, but a voluntary late return within 30 days sits at the bottom of the penalty scale. Waiting for the tax office to notice costs more.
I arrived mid-2025. Do these dates still apply to me?
Yes. Your first return covers the part of 2025 you were resident, and it runs on the same calendar. The arrival year guide explains the split.
Do the deadlines move when they fall on a weekend?
Check each deadline's governing rule. Article 60 fixes the normal June endpoint and conditional December endpoint irrespective of whether those dates are working days; do not apply a general weekend rule to every IRS deadline.
When exactly will my refund arrive?
Processing time varies with the return and any checks required. Use the assessment and refund dates published for the applicable campaign; a dated estimate is not a guarantee for an individual return.
CIRS article 60, checked 10 September 2026. This is a targeted primary-source correction, not professional sign-off of the whole guide.
Sources
- Autoridade Tributária e Aduaneira, official IRS calendar and Portal das Finanças notices (2026)
- Código do IMI, payment instalment rules
- Santander and Doutor Finanças 2026 tax calendar guides (checked August 2026)
This guide is general information, not personalised tax advice. Rules and rates change, and your facts can move you off the defaults described here. Confirm your position with a qualified professional before acting on it.