Most people log in to the Portal das Finanças, click into Modelo 3, get to the third field, and close the tab.
The form doesn't ask you anything unfair. It just asks you for things you didn't know you needed.
Here's the short list to have open on your desk, or, more realistically, in five browser tabs, before you start.
1. Your 2025 income summary, in EUR
What you need: total gross income for 2025, broken down by source (employer, pension provider, freelance client, rental property, brokerage), converted to Euros at the official European Central Bank year-end rate.
Where to find it:
- Employment income: W-2 (US), P60 (UK), or equivalent year-end summary from your employer
- Self-employed income: your recibos verdes total from the Finanças portal, plus any foreign self-employed income
- Pension income: SSA-1099 (US Social Security), provider statements (UK, US private pensions)
- Brokerage income: 1099-DIV, 1099-INT, 1099-B (US); year-end statement (UK)
- Rental income: lease statements + agent statements
The conversion rate that actually matters: the ECB publishes a year-end EUR conversion rate at https://www.ecb.europa.eu/. The Finanças accepts this rate. Don't use your bank's transfer rate; it'll be different and the AT will recalculate.
2. Documentation of foreign tax already paid
If you owe tax in another country on the same income, Portugal applies treaty relief, but only if you can document the foreign tax paid.
Acceptable documentation:
- US: Form 1040 (showing your filed return), plus any state return if applicable. If you haven't filed your 1040 yet for 2025, you can either file an extension and use estimates here, or wait and amend.
- UK: P60 showing PAYE deducted, plus HMRC self-assessment if you're not PAYE-only
- Brazil: Declaração de Ajuste Anual if filed
This is where it gets sequencing-tricky for Americans: the US filing deadline (April 15, with extensions to October 15) sits before Portugal's June 30. UK filing deadlines run later. We help clients navigate the order of filings. It matters more than people realize.
3. Validated e-fatura invoices for 2025
You don't bring these to the portal directly. They should already be sitting in your e-fatura account, properly categorized.
If they're not, this is the cutoff: you cannot retroactively validate 2025 invoices in June 2026. Validation closed in February 2026 for the 2025 tax year.
What this means practically:
- If you validated as you went, your deductions will auto-populate in Annex H. Beautiful.
- If you didn't, you've lost most of the deduction value for 2025. There are a few exceptions: health expenses with proper receipts can sometimes still be claimed. But the simple ones (general household, restaurant, pharmacy) are gone.
Lesson for 2026: validate monthly. We send our clients a one-line reminder the first Monday of every month.
4. Your NIF and Senha, both of them
The NIF (your 9-digit Portuguese tax ID) is the easy part. You know it, or it's on every Portuguese document you've ever signed.
The Senha is the password to the Portal das Finanças. It's separate from any other Portuguese login. It's sent by physical mail to your registered Portuguese address, typically arriving 5 to 10 business days after request. Longer if your registered address is out of date.
If you don't have a current Senha, request it now. Today. You will not get into the portal without it, and the deadline doesn't move because the post was slow.
Alternative logins exist (Chave Móvel Digital, Cartão de Cidadão) but require their own setup processes. For most first-year expats, Senha is the realistic path.
5. Your IBAN
Specifically, a Portuguese IBAN. The Finanças will deposit refunds to a Portuguese bank account. They will not deposit refunds to a foreign account.
If you've moved here and haven't opened a Portuguese account, that's the first project. Most expats use Millennium, ActivoBank, Bison Bank, or Revolut. Opening times range from same-day to two weeks depending on the bank and your documentation.
Have the IBAN ready when you start. The form asks for it in the Rosto (the main page), and the portal won't let you submit without one if you're expecting a refund.
A quick-start checklist
Print this. Pin it. Or save as a screenshot, whatever works.
- 2025 income totals in EUR (ECB year-end rate)
- Foreign tax documentation (W-2, P60, 1099s, etc.)
- E-fatura account checked, invoices validated (if not done, accept the loss and move on)
- NIF in hand
- Senha received and tested (log into the portal at least once before tax day)
- Portuguese IBAN ready
When you'd rather not
You don't have to do this yourself.
We file Portuguese tax declarations for expats at three fixed prices: €79 Prepared (we prepare the full Modelo 3 from your documents; you file it on the Portal yourself, no accountant signoff), €149 Signed & filed (our flagship: an OCC-registered Portuguese accountant reviews, signs off, and we file for you), and €300 Complex & priority. No hourly billing, no surprises, no AI sparkle icons. Two-business-day turnaround on the filing itself once we have your documents.