What's happening
This week marks the legal deadline for Portugal's tax authority to close out the 2025 income tax cycle. The Autoridade Tributária e Aduaneira (AT) had until 31 July 2026 to issue every taxpayer's nota de liquidação — the official assessment showing whether you're owed a refund or need to pay up — and any resulting balance, refund or debt must be settled by 31 August. This Friday, 31 July, marks the last day of the legal deadline for the tax authority to issue IRS assessment notices for income earned in 2025.
For foreign residents, this isn't a bureaucratic footnote. It's the moment the year's filing either gets confirmed as correct — or reveals an error that costs you money, delays a refund, or triggers a debt you didn't expect.
The dates that matter
The filing window for 2025 income ran from 1 April to 30 June 2026. The Tax Authority has until 31 July 2026 to issue the tax assessment notice, and any tax due must be paid by 31 August 2026, with refunds also processed by this date provided the return was submitted within the legal deadline.
Refunds often land before the notice itself even appears in the portal — taxpayers who are due a refund and provided their IBAN typically receive the bank transfer before the assessment notice reaches the Finanças portal, if the return was filed within the normal deadline — but 31 August remains the legal backstop. If you owe money, the notice tells you exactly how much and gives you the payment reference; miss the 31 August deadline and interest starts accruing. Late payment generates default interest of 4% per year and can lead to asset seizures. If you genuinely can't pay in one go, you can apply for an instalment payment plan electronically via the Portal das Finanças within 15 days of the payment deadline, and debts of €5,000 or less qualify for up to 12 instalments without providing guarantees, provided you have no other outstanding Tax Authority debts.
Errors foreign filers should catch now
Foreign residents' returns tend to be flagged more often than average, simply because they're more complex. A few things worth checking on your assessment before assuming it's correct:
Foreign-source income mismatches. Annex J covers income earned abroad — pensions, rental income, dividends, capital gains from other countries. Discrepancies here between what you declared and what the AT's cross-border data shows are a common source of delay or correction. Declarations involving different income categories, property, or income earned abroad are among the factors that can delay a refund even after the assessment is complete.
IBAN registration. This sounds trivial but causes real delays every year. The absence of a valid IBAN registered with Finanças is one of the most frequent causes of delay, and without one on file, the refund is issued by cheque and sent to the taxpayer's registered fiscal address instead of by bank transfer. If you've changed banks or your fiscal address is outdated, fix it now rather than waiting for a cheque to chase you around.
IFICI ("NHR 2.0") and remaining NHR holders. If you hold IFICI status or are still inside your original NHR 10-year window, check that the assessment actually applied the reduced rate to qualifying income. Errors in how income categories are coded can mean the AT taxes you at standard progressive rates instead of the 20% flat rate — an expensive mistake to leave uncorrected.
Pending tax debts absorbing your refund. If there are pending enforcement proceedings, the AT automatically uses the refund to settle existing debts — including old IMI or IUC arrears you may have forgotten about. Worth checking your full account status via the e-balcão rather than assuming silence means a clean slate.
Non-residents with Portuguese-source income. If you own rental property in Portugal but live elsewhere, you still had a filing obligation for 2025 — non-residents with Portuguese-source income such as rental income must also file. Confirm the assessment reflects the correct non-resident flat rates rather than resident scales.
If something looks wrong
If your assessment shows an error, a declaração de substituição (amended return) is still possible in some cases, though priority in processing can be lost once the original filing window has closed. If a refund simply hasn't arrived by 31 August and the return shows no irregularity, contact the AT through the e-balcão or its taxpayer line rather than waiting indefinitely.
What to watch next
Expect refund payments to keep landing through August, with cheques posted to those without a registered IBAN. Anyone who owes tax should confirm the payment reference now rather than in the final week — bank transfer, Multibanco and the AT app all work, but processing near the deadline gets congested. For a full walkthrough of Portugal's tax residency rules, filing categories and the IFICI regime, see our tax and NIF hub. If your assessment reveals errors involving foreign income, property or NHR/IFICI status, our tax support service can help you review the notice and, if needed, file a correction before the window closes.
Whatever your assessment shows this week, don't file it away unread — a five-minute check now can save weeks of chasing a refund or an unpleasant surprise come September.