COC for trailers, caravans and motorhomes
Updated 2026-09-01 · 5 min read
Trailers, caravans and semi-trailers are O-category vehicles, type-approved under Regulation (EC) 2018/858 alongside cars, and they receive their own Certificate of Conformity. Motorhomes are different again: they are M1 vehicles completed in stages, so their documentation reflects both the base chassis and the conversion.
Do trailers and caravans have a COC?
Yes, if they hold EU whole-vehicle type approval. O-category covers everything towed, from a small unbraked luggage trailer at O1 up to heavy semi-trailers at O4, and a caravan is simply an O-category trailer with living accommodation.
The certificate is shorter than a car's because there is no engine to declare, but it carries what a registration office needs: masses, axle loads, braking system and dimensions.
- O1: unbraked trailers up to 750 kg
- O2: trailers from 750 kg to 3.5 t, where braking becomes mandatory
- O3: trailers from 3.5 t to 10 t
- O4: trailers above 10 t
Why the masses on the COC matter
A trailer's certificate states its technically permissible maximum laden mass and its unladen mass. Those figures, combined with the towing capacity on the towing vehicle's own COC, determine what may legally be towed and which driving licence category is required.
This is the practical reason to keep both certificates together. A combination that looks fine on paper can exceed the tow car's approved capacity, and the two COCs are what settle the question at a roadside check.
How does multi-stage approval work for motorhomes?
A motorhome usually starts as a chassis-cab from a manufacturer such as Fiat, Mercedes-Benz or Ford, which is then completed by a converter. Under multi-stage type approval each stage has its own approval, and the final-stage manufacturer, the converter, issues the COC for the completed vehicle.
That is why a request to the chassis manufacturer for a motorhome's COC produces a certificate for the base vehicle only, if anything. The document a registration office wants comes from the converter and reflects the vehicle in its finished configuration.
Coceu identifies the correct issuing manufacturer from the VIN before a request is filed, which for converted vehicles is the difference between a usable certificate and a base-chassis document.
Key takeaways
- Trailers and caravans are O-category vehicles and receive their own COC.
- The categories run O1 to O4 by maximum mass, with braking mandatory from O2 upward.
- Trailer and towing-vehicle COCs together determine what may legally be towed and on which licence.
- Motorhomes are approved in stages, and the converter, not the chassis maker, issues the final COC.
Frequently asked questions
Does a small unbraked trailer need a COC?
To register it in another EU country, yes, provided it holds EU type approval. Many older or self-built trailers do not and need national individual approval.
Is a caravan COC different from a car COC?
It uses the same standardised form but omits engine data and focuses on masses, axle loads, braking and dimensions.
Who issues the COC for a motorhome?
The final-stage manufacturer, meaning the converter that completed the vehicle, not the manufacturer of the base chassis.
Do I need the COC of both the car and the trailer?
For registration you need the trailer's own certificate. Keeping both is useful because together they prove the combination is within the approved towing limits.