# Portugal tax and vehicle tax regulations

> Live situation record from CLSTR: https://clstr.news/situations/portugal-tax-and-vehicle-tax-regulations
> Updated: 2026-10-09T19:30:45.000Z. Sources: 6. Developments: 2.

Portuguese companies are managing various fiscal obligations throughout October 2026, including SAF-T billing file submissions, social security declarations, and VAT-related filings. 

In addition to these monthly deadlines, the government has announced a significant overhaul of the Unique Circulation Tax (IUC) payment schedule via Decree-Law no. 161/2026. Moving away from registration-month-based deadlines, the new system will introduce a fixed calendar. 

A transition period will begin on January 1, 2027, with payment structures varying based on the tax amount owed. A definitive model is scheduled to take effect on January 1, 2028, where payment frequency—ranging from a single annual payment to three installments—will be determined by the total IUC owed across all a taxpayer's vehicles.

## Timeline

### 2026-10-09: Portugal to change vehicle tax (IUC) payment schedule

Portugal will replace its vehicle tax (IUC) registration-month deadline with a fixed payment calendar starting in 2027, with a permanent tiered installment system arriving in 2028.

4 sources. https://clstr.news/cluster/portugal-to-change-vehicle-tax-iuc-payment-schedule

### 2026-10-02: Portugal tax deadlines for October 2026

Portuguese businesses must meet various tax and social security deadlines in October 2026, including SAF-T submissions, VAT declarations, and IUC installment payments.

2 sources. https://clstr.news/cluster/portugal-tax-deadlines-for-october-2026

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Cite as: Portugal tax and vehicle tax regulations. CLSTR, https://clstr.news/situations/portugal-tax-and-vehicle-tax-regulations