IRS Portugal March 2026 Tax Deadlines in Portugal

IRS Portugal deadlines for March 2026. Learn about e-Fatura validation, Modelo 10 submission, and key tax obligations in Portugal to stay compliant and avoid penalties.

IRS Portugal Calendar – March 2026 Deadlines

March is one of the most important months in the IRS Portugal calendar. Both individuals and businesses must comply with several tax obligations that directly affect their annual IRS declaration and overall tax compliance in Portugal.

From validating invoices to submitting Modelo 10 and payroll declarations, understanding these deadlines is essential to avoid penalties and ensure accurate reporting with the Autoridade Tributária e Aduaneira and the Segurança Social.

This guide provides a detailed overview of IRS Portugal obligations for March 2026, including a day-by-day calendar to help taxpayers in Portugal stay organized.

IRS Portugal – March 2026 Tax Calendar (Day-by-Day)

Date	IRS Portugal Obligation	Who Is Affected
2 March 2026	Final deadline to validate and classify 2025 invoices in the e-Fatura system for IRS deductions	Individuals, Employees, Freelancers
	Deadline to update household and personal tax data (marital status, dependents, address, residency)	Individuals and Families
	Submission of Modelo 10 for income not declared via the monthly payroll	Companies, Employers, Payors of Income
5 March 2026	Communication of invoice elements issued in February 2026	Businesses, VAT-registered entities
10 March 2026	Monthly Payroll Declaration to the Autoridade Tributária e Aduaneira and Segurança Social	Employers, Companies
15 March 2026	Intrastat declaration for EU goods transactions (if thresholds exceeded)	Companies trading within the EU
16 March 2026	Tax Authority publishes pre-calculated IRS deduction amounts in the tax portal	All IRS taxpayers
20 March 2026	Payment of withholding tax related to salaries, services, or rents paid in February	Employers, Companies, Landlords
25 March 2026	VAT payment under the monthly VAT regime (January 2026 VAT)	VAT-registered businesses
	Social Security contributions payment	Employers, Freelancers
31 March 2026	Submission of Modelo 30 (payments to non-residents)	Companies, International payers
	Submission of Modelo 38 and other specific tax communications	Companies with special reporting duties
	Deadline for VAT compensation scheme declarations (where applicable)	Eligible businesse

March 2, 2026

Deadline to validate 2025 invoices in the e-Fatura portal

This is the final day to confirm and classify all invoices issued in 2025. Proper validation ensures that expenses are correctly allocated for IRS Portugal deductions, including:

• Health expenses

• Education costs

• Housing expenses

• General family expenses

• Restaurant and accommodation expenses

• VAT deduction for specific sectors

Failure to validate invoices may result in losing eligible tax deductions.

Deadline to update household and personal information

Taxpayers must confirm or update:

• Marital status

• Dependents

• Shared custody arrangements

• Changes in tax residence

• Permanent residence details

Accurate information ensures correct IRS Portugal calculation and family taxation rules.

Submission of Modelo 10

Entities that paid income subject to withholding tax but not declared through the monthly payroll declaration must submit Modelo 10. This applies to certain categories of income paid to individuals.

March 5, 2026

Communication of invoice elements

Businesses must report invoice details for the previous month to the tax authorities. This is mandatory for VAT-registered entities operating in Portugal.

March 10, 2026

Monthly Payroll Declaration

Employers must submit the monthly payroll declaration to the tax authorities and to Segurança Social. This includes:

• Employee salaries

• Withholding tax amounts

• Social security contributions

This obligation affects both IRS Portugal compliance and social contribution records.

March 15, 2026

Intrastat Declaration (where applicable)

Companies exceeding EU trade thresholds must submit Intrastat declarations for goods traded within the European Union.

March 16, 2026

Publication of Deduction Amounts by the Tax Authority

The tax authority makes available the calculated deductible expenses for IRS Portugal purposes in the taxpayer’s portal.

Taxpayers should review:

• General family expenses

• Health deductions

• Education deductions

• Housing interest (where applicable)

If discrepancies are found, corrections may need to be submitted within the official contestation period.

March 20, 2026

Withholding Tax Payment

Companies must pay withholding tax amounts collected in February 2026.

This includes:

• Salary withholding

• Professional services withholding

• Rental income withholding

Failure to pay on time may result in penalties and interest charges.

March 25, 2026

VAT Payment (Monthly Regime)

Businesses under the monthly VAT regime must submit and pay VAT due for January 2026.

Social Security Contributions Payment

Employers and independent workers must ensure social contributions are paid by this date.

March 31, 2026

Final March Compliance Deadlines

Several additional reporting obligations may fall on this date, including:

• Modelo 30 (payments to non-residents)

• Modelo 38 (transfer pricing or other specific communications)

• VAT compensation scheme declarations (where applicable)

Businesses operating internationally or making payments abroad should pay particular attention to this deadline.

Key IRS Portugal Compliance Tips

1. Do not wait until the last day to validate invoices.

2. Always confirm household data before IRS submission season.

3. Employers must ensure payroll declarations match withholding payments.

4. Independent workers should verify that all issued invoices are properly reported.

5. Businesses should review whether Modelo 10 applies to their operations.

Who Is Affected by the IRS Portugal March Deadlines?

The March 2026 IRS Portugal calendar applies to:

• Employees

• Independent workers (trabalhadores independentes)

• Landlords

• Companies and SMEs

• Foreign residents with Portuguese tax residency

• Employers operating in Portugal

Whether you are an individual or a company established in Portugal, these obligations are part of the mandatory annual tax cycle.

Final Thoughts on IRS Portugal March 2026

March is a decisive month in the IRS Portugal tax cycle. Even though the annual income tax return is filed later, the actions taken during March directly influence:

• Final tax liability

• Refund amounts

• Deduction eligibility

• Compliance status with Portuguese authorities

Staying informed and proactive is essential for individuals and businesses operating in Portugal. Proper planning during March ensures a smoother IRS Portugal filing season in the months ahead.