Tax authority opens tender to overhaul car tax collection system
The Portugal Tax and Customs Authority has launched an international public tender worth €225,000 to reconfigure its internal IT systems for the new Single Circulation Tax (Imposto Único de Circulação, IUC) payment schedule that takes effect next year.
The procurement notice was published in Diário da República and the Official Journal of the European Union. Companies providing consultancy and software programming services have until 17:00 on 30 October to submit bids.
Why the systems need changing
The tax authority must adapt its collection platform to handle fixed payment dates, moving away from the current model where IUC falls due in the month a vehicle was first registered.
The contract covers what the tender describes as "corrective and procedural management" of tax assessment and collection under the new regime established by Decree-Law No. 161/2026 of 4 August.
Until the end of this year, vehicle owners continue paying IUC in the month of the vehicle's registration anniversary.
What changes for drivers in 2027
The transitional rules for 2027 aim to prevent taxpayers from having to pay both the 2026 and 2027 tax bills within a short interval.
Under the transitional regime:
• IUC up to €500: paid in a single instalment during October
• IUC above €500: paid in two instalments, in July and October, with the option to settle the full amount in July
The Government created this schedule to avoid situations where taxpayers would face two payments close together during the switch between systems.
Owners may also request cancellation of the 2027 IUC assessment if they cancel a vehicle registration in categories A, B, C, D or E before the registration anniversary date.
Fixed dates from 2028 onwards
The definitive regime takes effect in 2028. The Portugal Tax Authority will issue a single annual assessment per taxpayer covering all vehicles registered in their name on 1 January.
Payment schedules from 2028:
• Up to €100: single payment by end of April
• Between €100 and €500: two instalments, April and October
• Above €500: three instalments, April, July and October
Taxpayers entitled to split payments may opt to pay the full amount in April instead.
The Government states the changes seek to promote voluntary compliance, streamline procedures and prevent situations that penalise taxpayers, according to the decree-law text. The new calendar mirrors the system already used for the Municipal Property Tax (Imposto Municipal sobre Imóveis, IMI).
Political backing
Parliament approved the legislative authorisation on 17 April with votes in favour from the centre-right PSD, CDS-PP, centre-left PS, left-wing Livre and the JPP, while the far-right Chega, the communist PCP, left-wing BE and the animal rights party PAN abstained.
The legislation affects only the payment calendar — the IUC calculation formula remains unchanged. For a household with two cars and an annual IUC totalling €600, the 2028 regime would split payments across April, July and October, rather than requiring payment in two different months tied to each vehicle's registration date.
