The Modelo 3 IRS return for 2025 income was due from 1 April to 30 June 2026, or until 31 December 2026 where the AT was notified on or before 30 June that the creditable foreign tax was undetermined (CIRS art. 60). IMI up to EUR 100 is paid in May, up to EUR 500 in May and November, and higher amounts in May, August and November (CIMI art. 120(1)).
Month-By-Month 2026 Tax Calendar
Selected 2026 dates. Confirm the tax year, conditions and any applicable notice or extension with the official source.
January
- Portugal
IFICI registration: 15 January for people becoming resident in 2025; late registration may leave a shorter benefit period
Tax deadline
- UK
2024/25 online Self Assessment and balancing payment, 31 January
Tax deadline
- Portugal
Self-employed quarterly declaration for Q4 2025, where required
Tax deadline
February
- Portugal
Long-term rental contract information, where required, 16 February
Tax deadline
- South Africa
Second provisional payment for a February year-end, 27 February
Tax deadline
March
- Portugal
2025 e-Fatura validation and household information, 2 March
Tax deadline
- Canada
2026 quarterly instalment, where required, 16 March (15 March is Sunday)
Tax deadline
- Portugal
Before filing: check residence period, regime status and foreign-income evidence
Planning reminder
April
- Portugal
Ordinary 2025 income Modelo 3 filing window opens, 1 April
Tax deadline
- US
Ordinary 2025 Form 1040 deadline, 15 April; interest on unpaid tax runs from this date
Tax deadline
- US
2025 FBAR due 15 April, with automatic extension to 15 October
Tax deadline
- Germany
2024 return prepared by a tax adviser, 30 April; individual notices may set an earlier date
Tax deadline
- Canada
Most 2025 T1 returns and balance due, 30 April
Tax deadline
- Portugal
Self-employed quarterly declaration for Q1 2026, where required
Tax deadline
May
- Portugal
IMI: single payment up to EUR 100, or first instalment above EUR 100; follow the collection notice
Tax deadline
June
- US
2025 Form 1040 automatic overseas extension, 15 June, for qualifying taxpayers; interest still runs from 15 April
Tax deadline
- Canada
Self-employed 2025 return, 15 June; balance was due 30 April
Tax deadline
- Canada
2026 quarterly instalment, where required, 15 June
Tax deadline
- Portugal
Ordinary 2025 Modelo 3 deadline, 30 June; check any applicable statutory extension
Tax deadline
- Portugal
2025 Modelo 22 for calendar-year taxpayers: extended deadline, 30 June
Tax deadline
July
- Portugal
2025 IES/DA for calendar-year filers, where required, 15 July
Tax deadline
- Germany
Ordinary 2025 return without a tax adviser, 31 July, where filing is required
Tax deadline
- Portugal
Self-employed quarterly declaration for Q2 2026, where required
Tax deadline
August
- South Africa
First provisional payment for a March-start year, 31 August
Tax deadline
- Portugal
IMI: second instalment when the assessment exceeds EUR 500; follow the collection notice
Tax deadline
September
- Canada
2026 quarterly instalment, where required, 15 September
Tax deadline
- Portugal
AIMI payment, where due; follow the collection notice
Tax deadline
October
- UK
Notify a new 2025/26 Self Assessment obligation by 5 October; paper return due 31 October
Tax deadline
- US
2025 Form 1040 due 15 October if a valid extension applies; payment interest is not extended
Tax deadline
- US
Automatic extended 2025 FBAR deadline, 15 October
Tax deadline
- South Africa
2026 filing season deadline for non-provisional individuals, 23 October
Tax deadline
- Portugal
Self-employed quarterly declaration for Q3 2026, where required
Tax deadline
November
- Portugal
IMI: second instalment above EUR 100 up to EUR 500, or third above EUR 500; follow the notice
Tax deadline
December
- Canada
2026 quarterly instalment, where required, 15 December; different rules apply to farmers and fishers
Tax deadline
- Portugal
Review residence dates, planned disposals and enacted rules for the next year
Planning reminder
- South Africa
Prepare for the provisional-taxpayer return deadline on 22 January 2027
Planning reminder
- US
Gather year-end account balances and investment records for the next filing cycle
Planning reminder
How To Use This Calendar
Tax compliance in Portugal is year-round. Use this page as a planning map and confirm year-specific filing windows in official calendars before submission.
Use this page to plan key Portuguese compliance checkpoints across the full year.
Portugal tax compliance works best when you treat the calendar as a year-round system, not a once-a-year checklist. January sets the base for residency-driven decisions, and the rest of the year follows in predictable cycles for filing, payment, and evidence control.
For self-employed taxpayers, Social Security follows a rhythm: quarterly declarations in January, April, July and October for the preceding quarter, and monthly contribution payments from the 10th through the 20th.
2026 Planning Checkpoints
- Q1 readiness: close prior-year records, validate e-Fatura, and clean deduction evidence before pre-filing checks.
- IRS for 2025 income: the ordinary filing window ran from 1 April to 30 June 2026 and has closed. If a return remains outstanding or needs correction, confirm the applicable procedure and whether the conditions for a statutory extension were met.
- Corporate/property cycle: for companies whose tax year is the calendar year, the 2025 IRC Modelo 22 return and payment, due on the last day of May (CIRC arts 104(1)(b) and 120(1)), could be made until 30 June 2026 under Despacho 81/2026-XXV; IMI is paid in one to three instalments between May and November, depending on the amount (CIMI art. 120(1)), and AIMI in September (CIMI art. 135-H(1)).
- Cross-border overlay: align Portuguese steps with any US/UK reporting duties to avoid sequencing errors.
Use this page to plan, and confirm the exact current-year date shifts in official calendars before submission.
Key Deadlines For US Expats
US taxpayers in Portugal often manage parallel Portuguese and US filing obligations.
The risk is not only missing a deadline, but filing in the wrong sequence with incomplete records.
Start by separating account-reporting duties (FBAR) from tax-return duties (Form 1040 and Form 8938). Then map deadlines and extension mechanics together so your Portuguese and US timelines do not collide.
Core US Checkpoints
- FBAR: applies when aggregate foreign accounts exceed USD 10,000 during the year; due 15 April with automatic extension to 15 October.
- Form 1040 (abroad): automatic extension to 15 June for qualifying taxpayers abroad, with procedural extension options beyond that date.
- Form 8938: filing depends on threshold tests, including year-end and anytime-during-year tests for taxpayers abroad.
If you have mixed-source income, build one evidence pack that supports both jurisdictions to reduce rework and audit friction.
Key Deadlines For UK Expats
Use this page to plan UK filing and payment obligations while resident in Portugal.
Plan them early so they do not conflict with your Portuguese filing workflow.
- 31 January 2026: Online Self Assessment returns and balancing payments for 2024/25 are due, with the first payment on account for 2025/26 where applicable.
- 31 July 2026: The second Self Assessment payment on account for 2025/26 is due where applicable.
- 5 October 2026: The deadline to register for a first or reactivated Self Assessment return for 2025/26.
- 31 October 2026: HMRC must receive paper Self Assessment returns for 2025/26 by the standard filing deadline.
- Confirm your residence and foreign-income treatment in the same planning cycle.
Penalties For Late Filing And Payment
Late filing or payment can create avoidable financial and administrative exposure.
That exposure can include statutory fines, default interest, and additional procedural burden.
- Portuguese outcomes depend on tax type, delay duration, and case facts.
- US FBAR/FATCA penalties are separate from Portuguese penalties and follow US rules.
- Use current-year official notices before estimating monetary exposure.
Keep One Usable Tax Calendar
Keep a calendar for the obligations that apply to you.
- Save each tax notice with its stated response or payment deadline.
- Label each filing by income year, country and return type.
- Set reminders early enough to obtain missing statements or assessments.
- Retain the filed return, submission receipt and proof of payment together.
- Revisit dates when residence, employment, business activity, assets or an authority notice changes.
A reminder is not a statutory extension. If a deadline has passed or essential documents are delayed, establish the available filing or correction procedure for that obligation.
Final Thoughts
Consistent timing is the safest approach to Portugal tax compliance.
Most tax problems come from timing gaps, not from complex strategy errors.
When you plan early, keep evidence organised, and review deadlines before each filing cycle, compliance becomes predictable.
Taxbordr helps you do this with clear advice, source-backed guidance, and a plan matched to your situation.
| Compliance area | Filing point | Records to retain |
|---|---|---|
| Portugal IRS Filing Window | Annual filing period with statutory deadlines and late-filing exposure. | Income statements, deductible invoices, residency documentation. |
| IRC Payments on Account | Corporate prepayments follow statutory schedule for applicable entities. | Prior-year tax computation, accounting trial balance, payment receipts. |
| IMI/AIMI Property Cycle | Property tax exposure depends on assessed value and legal thresholds. | Caderneta predial, ownership records, tax assessment notices. |
| US FBAR/Form 8938 Overlay | Separate US reporting may apply alongside Portuguese obligations. | Account statements, year-end balances, foreign asset inventory. |
Frequently Asked Questions
What happens if I miss the Portuguese IRS filing deadline?
If the deadline has passed, establish whether the return is missing or needs correction and whether an ordinary or special deadline applies. Late filing and late payment have different consequences. Gather any AT notice and prior return, and contact Taxbordr to confirm the filing or correction scope before payment. Do not wait for a further notice if a required return remains outstanding.
Do I owe corporate estimated payments if last year was weak?
It depends on prior liability and current legal framework. Confirm calculations before skipping any payment window.
Why does e-Fatura validation matter?
Correct invoice validation and categorisation supports deduction treatment in your Portuguese IRS return.
I am a US citizen in Portugal. Which filings can apply?
You may have parallel Portuguese and US obligations. Scope depends on residency, income type, and threshold tests.
What is IFICI and when should I apply?
IFICI is Portugal's post-NHR incentive regime for qualifying activity. Registration is due on or before 15 January of the year after the year in which tax residence begins (Portaria 352/2024/1, art. 2(1)); for residence starting in 2026, that is 15 January 2027. A late registration takes effect only from the year in which it is made, for the rest of the ten-year period (EBF art. 58-A(7)).
I own Portuguese property. Which taxes usually matter most?
IMI (annual municipal property tax), AIMI (additional property tax where applicable), and IMT (transfer tax at acquisition).
Related guides
- Guide · IRS 2025 in Portugal: correct a return or file lateThe Modelo 3 IRS return for 2025 income, with foreign income normally on Anexo J, was due from 1 April to 30 June 2026 (CIRS art. 60(1)).
- Guide · Moving to Portugal: tax checklist for 2026Plan the tax steps before and after a move to Portugal: home-country departure, tax residence, NIF, income records, IFICI and your first return.
- Article · Portugal 2025-2029 Tax Plan: Proposed vs EnactedThe IRS rate cuts in Portugal's 2025-2029 government programme are law for 2025 and 2026, in CIRS art. 68; later cuts remain proposals.