Portugal tax deadlines stay in force throughout August

Portugal’s fiscal holiday for August does not cancel tax obligations. While the regime allows some filing dates to be extended to the end of the month or into September, many responsibilities retain their usual deadlines. Companies, self‑employed workers and other taxpayers must still submit withholding tax (IRS and IRC) returns normally due by the 20th, comply with VAT obligations for small retailers, and file the SAF‑T invoice file by month‑end. Payroll declarations to the tax authority and social‑security contributions also remain unchanged.

Corrections to previous returns follow specific rules: a replacement IRS declaration (Model 3) must be filed within 30 days of the original deadline or of the event prompting the change, while certain foreign‑source income may be deferred until 31 December. For corporate tax (IRC), amendments that increase tax can be submitted late, but reductions must be filed within a year of the original deadline. Ignoring these rules can lead to penalties despite the perceived slowdown in August activity.