Portugal Tax Calendar: The Deadlines That Repeat Every Year

• IRS is filed from 1 April to 30 June, and 30 June does not roll to Monday (CIRS art. 60.º n.º 1). Payment or refund for an on-time return is due by 31 August.
• VAT returns are due on the 20th and payment on the 25th of the second month after the period. June and the second quarter move to 20 and 25 September (CIVA arts. 27.º and 41.º).
• A freelancer's Social Security declaration is due at the end of January, April, July and October, and the monthly contribution is paid between the 10th and 20th of the following month.
• IMI is paid in May, or May and November, or May, August and November, depending on the bill. AIMI is assessed in June and paid in September.
• Freelancers in category B also make IRS payments on account on 20 July, 20 September and 20 December (CIRS art. 102.º).

Most Portuguese tax dates are fixed in the law and repeat every year. IRS is filed from 1 April to 30 June. VAT returns are due on the 20th of the second month after the period and payment on the 25th. Freelancers file a Social Security declaration at the end of each quarter and pay IRS on account on 20 July, 20 September and 20 December. IMI is paid in May, August and November, and AIMI in September. The exceptions are the AT's own February and March dates, which it prints each January.

How to read this calendar

There are two kinds of date here. Statutory dates are written in a code and stay the same until the code is amended: 30 June for Modelo 3, the 20th and 25th for VAT, 20 July for the first payment on account. Operational dates are the ones the AT publishes for the IRS season each year, in a leaflet of main deadlines, such as the end-of-February deadline to check your invoices. Where a date below comes from that leaflet, it is labelled as the 2026 season's, and you should look for the new leaflet each January instead of assuming the same day.

Weekends matter. Art. 20.º n.º 1 of the tax procedure code (CPPT) moves a deadline that ends on a day when the offices are closed to the next business day, and the AT applies it to its own calendar: in 2026 it moved an end-of-February deadline from Saturday 28 February to Monday 2 March. Two dates in this guide are written so that it does not apply, and they are named below. Public holidays are handled by the same article, but this guide does not list them, so check a deadline that lands near one.

Month by month

Employees and other IRS filers

For most people the year has one busy season. Before the return opens, the AT asks you to check your household as it stood on 31 December and to verify the invoices behind your deductions, and the leaflet gives the end of February for both. In 2026 it then opened a window from 16 to 31 March to see the deductible expenses the AT had calculated and to claim anything missing. The return itself runs from 1 April to 30 June, and a clean case may only need you to confirm the automatic assessment: see the IRS filing guide and the guide to IRS Automático. After you file, the AT's normal deadline to assess is 31 July, and it names 31 August as the date to pay or receive a refund for returns filed on time.

Two items surprise people. The 30 June deadline is written with the words «independentemente de este dia ser útil ou não útil», so if it falls on a Sunday, the deadline is that Sunday. And if you have foreign income and a right to a foreign tax credit that the source country has not yet fixed, art. 60.º n.º 3 extends the deadline to 31 December of that year, but only if you told the AT within the normal window that you meet the conditions.

Freelancers: three calendars running together

A freelancer on green receipts has a Social Security calendar, a VAT calendar and an IRS one, and they do not line up. Social Security is quarterly for the declaration and monthly for the payment: you declare at the end of January, April, July and October, and each monthly contribution is normally paid between the 10th and 20th of the following month. The quarterly declaration guide has the detail, including the rollover that made the October 2026 deadline fall on Monday 2 November.

VAT follows the turnover of the previous year. At €650,000 or more you file monthly, and below it quarterly, though a quarterly filer can opt for monthly (CIVA art. 41.º). Either way the return is due by the 20th of the second month after the period and payment by the 25th (art. 27.º). A monthly filer repeats this every month. The one exception is June and the second quarter, which run to 20 and 25 September. Whether you charge VAT at all is a different question, covered in the VAT guide for freelancers.

IRS payments on account come from art. 102.º. Anyone with category B income makes three of them, by the 20th of July, September and December, together equal to 65% of a formula built on the tax of the year before last. The amount is set by the AT and comes with the assessment notice, and none is due if it is below €50. They stop when your withholdings and payments already cover the year's tax, or when you stop earning category B income, and you can reduce them if you expect to owe less, at the risk of compensatory interest if that leaves you more than 20% short of what you would normally have paid. The ones you make are credited against the tax you owe when you file.

Property owners

IMI is paid in May when the bill is €100 or less, in May and November when it is above €100 and up to €500, and in May, August and November above €500 (CIMI art. 120.º n.º 1). Spouses and de facto partners are treated together for the instalment thresholds, on the whole tax, even for co-owned property, when the property is their permanent home and their tax address (n.os 6 and 7). AIMI is separate: the AT assesses it in June from the register on 1 January, and it is paid in one payment in September. The IMI guide and the AIMI guide explain how each amount is worked out.

What this calendar leaves out

It covers the taxes an individual in Portugal meets most often. It leaves out corporate income tax, stamp duty and IUC, the vehicle tax. IUC is left out on purpose: its payment month depends on the vehicle and the rules around it are being changed, and the AT's code text for it could not be checked on the day this page was written, so no date is given rather than a guess. A date you rely on for money should be checked against the AT's own Agenda Fiscal or the notice you received.

Checklist

• In January, look for the AT's leaflet with the main IRS dates for the season and note its February and March dates.
• Put 30 June in your diary as a fixed date that does not roll, and file before it if you can.
• If you are a freelancer, add the four Social Security declaration dates, the monthly 10th to 20th payment window, and 20 July, 20 September and 20 December.
• If you file VAT, add the 20th and 25th for your regime, and remember that June and the second quarter move to September.
• If you own property, add the IMI months that match your bill and the September AIMI payment.
• Read each notice from the AT or Social Security for its own date, because it decides for you.