The ordinary online deadline for the Portuguese IRS Modelo 3 return covering 2025 income was 30 June 2026. The date does not mean everyone living in Portugal had to submit a return, or that tax was payable that day.
What the deadline covers
Article 60 of the IRS Code sets the ordinary electronic filing window from 1 April to 30 June of the following year. Filing and payment are separate: if AT issues an assessment, read the payment date on that notice rather than assuming it is the filing deadline.
Article 60 also provides a conditional extension to 31 December where qualifying foreign tax for a double-taxation credit has not been determined by the ordinary deadline. It requires a communication to AT within the ordinary filing window. It is not a general extension for everyone with foreign income.
Check whether you needed to file
Article 57 sets out the annual return obligation, while article 58 lists exemptions. Residence, income type, withholding and any exemption all matter. A visa category alone does not establish Portuguese tax residence or a Modelo 3 filing obligation.
Under article 16, residence can arise through more than 183 days in a relevant 12-month period or a qualifying habitual home, among other rules. Article 15 distinguishes the income scope for residents and non-residents. If you moved during 2025, establish your residence dates and income periods before deciding what to declare. Article 57 addresses years with both resident and non-resident status.
Prepare the return from your records
If you needed to file, make a dated residence timeline and an income list before selecting annexes. Match each item to a statement or other record, and keep evidence of foreign tax where you claim relief. Check any applicable deductions and your e-Fatura information. The relevant fields depend on your income and filing position; an IBAN or foreign-tax entry is not universal.
For income expressed in another currency, keep the original statement and document the conversion method required for that payment. Article 23 sets different exchange-rate rules depending on when and where income is paid or transferred. There is no single ECB year-end rate to apply to every foreign-income item.
If the date has passed
First confirm whether you were required to file. If you were, establish the correct return and submit or correct it promptly through the Portal das Finanças, keeping the submission receipt. Check any AT notices and the payment date on an assessment. Late-filing penalties and payment interest depend on the facts; do not rely on a generic amount or an assurance that no other action can follow. See RGIT article 116 and IRS Code article 110.
If this is your first return
Test portal access early and confirm that your registered details are current. Review the first Modelo 3 guide for the filing sequence, and use the first-filing checklist to track records and unresolved questions. If residence starts partway through the year, foreign income, a treaty, or a special regime changes the position, get fact-specific advice before submitting.
This is general information, not a determination that you must file or a calculation of your liability.