Start with five groups of records: income, foreign tax, expenses, access details and bank details. Use the interactive first-filing checklist to track preparation, then follow the Modelo 3 filing guide when the records are ready.
Updated 15 September 2026. Editorial check against official sources. Professional review has not been recorded.
1. Income records for the relevant year and residence period
Collect employer and pension statements, self-employment records, rental statements and investment reports that apply to you. Keep the original amounts, currencies, payment dates and gross income separate from tax withheld and the net amount received.
A foreign annual statement is a starting record, not necessarily the figure to copy into Modelo 3. Its tax year, income categories or reporting period may differ from Portugal's. If you moved during the year, prepare a dated residence timeline before deciding which income belongs in each period. The arrival-year guide explains that distinction.
Do not convert every receipt at a blanket year-end rate. CIRS article 23 generally links the official currency conversion to the relevant payment or availability date; 31 December is a fallback when those dates cannot be proved. Keep the dates and conversion basis with your records. Accounting-based cases follow their applicable rules.
2. Evidence of foreign tax paid
Keep the foreign assessment and evidence connecting tax actually paid to the income, country and person concerned. An estimated liability, withholding amount and final tax paid are different figures; label them separately.
AT's international tax FAQ specifies tax-authority-issued or authenticated evidence for proving foreign income and tax. A payroll or broker statement alone should not be assumed to settle every evidence requirement.
Use the Anexo J guide for the income-source and foreign-account questions. A foreign tax credit has conditions and limits; it is not an automatic refund of every foreign payment.
If a qualifying foreign tax amount is still undetermined, article 60 provides a conditional extension to 31 December, with notification to AT within the ordinary filing window. Do not assume a foreign filing extension automatically extends the Portuguese deadline.
3. Expense records and the portal's deduction information
Gather invoices and supporting records for expenses you intend to claim. Compare them with the information in e-Fatura and the relevant IRS deduction area, noting missing or disputed entries and the category involved.
Check the applicable year's AT instructions before correcting an entry or changing Anexo H. Deadlines and procedures matter, and the treatment is not identical for every expense category. Do not assume that every missing invoice can be added at filing time, or that every deduction is automatically lost.
Keep a short issue list: expense date, category, amount, supporting record and the question to resolve. This is more useful than a folder of unexplained screenshots.
4. NIF and tested portal access
Have your NIF available and test your own Portal das Finanças login before the filing deadline. Resolve access problems through the portal's official authentication or recovery options. Keep passwords and authentication codes out of shared document packs.
Check the personal details shown in the account against your records. A NIF or an address update does not, by itself, answer the legal residence question. Start with the tax-residency guide if the dates are uncertain.
5. Bank details and confirmation of ownership
Check the IBAN recorded with AT and its confirmation status. AT's bank-details guidance says validation depends on confirmation of account ownership and explains that another IBAN may be indicated on Modelo 3 for an IRS refund.
Keep a bank-issued ownership document available if confirmation is needed. Follow AT's process for your account; do not assume that opening a new Portuguese bank account is a prerequisite for preparing the return.
Turn the records into a filing pack
Create one folder per income year. Add a residence timeline, an income schedule, foreign-tax evidence and a list of unresolved questions. Link each figure to a record so that you or a reviewer can retrace it.
Open the first-filing checklist to work through the checks. It runs in your browser and does not ask you to upload private tax documents.
The 2027 campaign's forms and preparation deadlines need checking when AT publishes them. This is general preparation guidance, not a completed return or individual tax advice.