The document that unlocks vehicle registration – COC
If you have ever imported a car into Portugal or any other EU member state, you have almost certainly come across the term Certificate of Conformity (COC) — commonly known by its acronym COC. Despite being one of the most requested documents in the vehicle import process, it is also one of the most misunderstood. This guide explains exactly what a COC is, what information it contains, and why it is so important for anyone looking to legally drive an imported vehicle in Europe.
Definition: what exactly is a Certificate of Conformity?
A Certificate of Conformity (COC) is an official document issued directly by the vehicle manufacturer — not by a third party or government body — that certifies a specific vehicle complies with all applicable EU directives and regulations at the time of its production. Think of it as the vehicle’s identity card from the factory. It proves that the car, motorcycle, van, or other vehicle type was built according to the technical standards required for road use across the European Union.
The COC is based on the European Whole Vehicle Type Approval (WVTA) system established under EU Directive 2007/46/EC, later updated by Regulation (EU) 2018/858. Under this framework, once a vehicle model receives type approval, the manufacturer must supply a COC with every unit sold.
What information does a COC contain?
A standard COC document is divided into several numbered sections, each covering a different technical aspect of the vehicle. The most important fields include:
- Vehicle identification number (VIN) — the unique 17-character code that ties the document to a specific unit
- Make, model, and variant — the commercial name and internal classification used by the manufacturer
- Engine data — displacement in $\text{cm}^3$, maximum net power in kW, fuel type, and Euro emissions standard
- Dimensions and mass — wheelbase, track widths, maximum authorised masses for each axle
- Environmental data — $\text{CO}_2$ emissions in g/km and fuel consumption figures
- Type approval number — the official EU code confirming the model passed homologation
- Safety systems — ABS, ESP, airbag count, and other active or passive safety features
This level of detail is precisely what national registration authorities — such as Portugal’s IMT (Instituto da Mobilidade e dos Transportes) — need to assign the correct fiscal and technical classification to your vehicle.
COC vs. other vehicle documents
Many people confuse the COC with other papers that accompany a vehicle. Here is a quick comparison of the most common documents:
| Document | Issued by |
| Certificate of Conformity (COC) | Vehicle manufacturer (OEM) |
| Vehicle registration certificate | National authority (e.g. IMT in Portugal) |
| Owner’s manual / service book | Manufacturer — not a legal document |
| Individual approval certificate | National technical authority (for one-off approval) |
| Invoice / bill of sale | Seller — commercial document only |
The COC is the only document in this list that simultaneously carries technical, legal, and fiscal weight at a European level.
Why is the COC required for registration in Portugal?
When you import a used vehicle into Portugal, the IMT requires a COC to process the registration request and calculate ISV (Imposto Sobre Veículos — the Portuguese vehicle tax). Without a valid COC, the registration process stalls. The vehicle cannot receive a Portuguese licence plate, cannot be legally insured as a registered vehicle, and cannot be driven on public roads.
The COC also directly affects the ISV calculation. Since 2023, vehicles that can demonstrate a low $\text{CO}_2$ figure via their COC benefit from reduced ISV rates, while older or higher-emission vehicles attract higher charges. Getting the COC right — and getting it from the original manufacturer — is therefore not just a bureaucratic formality. It has a direct financial impact.
Does every vehicle need a COC?
Most modern vehicles manufactured after 1996 and sold in the EU have been type-approved under the WVTA framework and therefore have a COC on file with the manufacturer. However, there are some important exceptions:
- Vehicles manufactured before the EU type-approval system was introduced (generally pre-1996 for cars) may not have a COC and require individual homologation instead
- Vehicles imported from outside the EU — from the United States, Japan, or Australia — were not type-approved under EU rules and will also need individual approval
- Heavily modified vehicles may have lost their original type approval, meaning the existing COC is no longer valid
For all other cases — which represent the vast majority of used car imports within Europe — obtaining the original manufacturer COC is both possible and highly recommended.
How long does it take to get a COC?
Delivery times vary significantly depending on the manufacturer. German brands such as Volkswagen Group (VW, Audi, Porsche, SEAT, Škoda) and BMW Group tend to process requests within 3 to 7 business days. French brands (Renault, Peugeot, Citroën) typically take 5 to 10 business days. Some premium brands — Mercedes-Benz, for example — can take up to 25 business days due to internal archiving processes.
Working with an authorised COC provider that has direct relationships with manufacturer databases significantly reduces waiting times and eliminates the risk of receiving an incorrect or incomplete document.
Need your COC fast? COC-Express.eu delivers original manufacturer certificates for all major brands. Check delivery times and prices at coc-express.eu
