CBAM verification is the step that turns supplier emissions data into a number the European Union will accept, and it is about to become concrete. The first accredited CBAM verifiers are expected around September 2026, which is also when the verifier module in the CBAM Registry opens. For importers, that starts the clock on the first verified annual declaration, due 30 September 2027.
Verification is often the last item on the CBAM project plan. It deserves to be higher, because a verifier can only confirm data that already exists, in a form that can be traced back to an installation. Everything that makes verification possible has to be arranged before the verifier arrives.
Why CBAM verification matters
During the transitional period, importers reported embedded emissions without independent assurance, and gaps were routinely filled with default values. In the definitive regime, the annual CBAM declaration must report verified emissions.
That changes the economics of data quality. Actual emissions data, once verified, will often be lower than the applicable default values, and the difference translates directly into certificates you do not have to buy. Our article on CBAM default values and why they matter explains the size of that gap for typical goods. Verification is the gate between the two.
Who can act as a CBAM verifier
Verification cannot be done in house, and it cannot be done by any consultant. Under Article 18 of the CBAM Regulation and Commission Delegated Regulation (EU) 2025/2551, a verifier must be a legal entity accredited by a national accreditation body, having demonstrated the required technical competence and independence.
Two points regularly cause confusion:
- Third country verifiers are allowed, but the accreditation must come from an accreditation body in the European Union. A body accredited only under a national scheme outside the EU does not qualify.
- Accreditation is sector specific. A verifier accredited for one activity scope cannot simply extend it to another, which matters if your imports span steel, aluminium and fertilisers.
The Commission maintains the authoritative position on which verifiers hold accreditation. Until an accreditation is actually published, a promise of imminent accreditation is not something to plan around.
The rules that govern verification
Two instruments do the heavy lifting. Delegated Regulation (EU) 2025/2551 governs the accreditation of verifiers, and Implementing Regulation (EU) 2025/2546 sets the verification principles themselves: what the verifier examines, how findings are classified, and what the verification report must contain. A guidance document on accreditation and verification followed in the summer of 2026.
The underlying framework is Regulation (EU) 2023/956, in its consolidated version of 20 October 2025, which incorporates the simplification amendments including the 50 tonne de minimis threshold that keeps most very small importers out of scope entirely.
Site visits in the first year
In the first year of verification, the verifier is required to carry out an on-site inspection of the installation where the relevant goods are produced. Implementing Regulation (EU) 2025/2546 defines the narrow circumstances in which a virtual visit or a waiver is possible, and the verification report has to record the details of the visit and the reasons behind the choice.
This is the requirement most likely to surprise a procurement team. It means a verifier travelling to a mill or smelter in a third country, arranged through your supplier, scheduled far enough ahead to fit the verifier's capacity. Suppliers who have never hosted such a visit will need notice, and contracts drafted before CBAM may not oblige them to grant access at all.
The timeline to 30 September 2027
The sequence is tighter than the dates suggest:
- September 2026. First accreditations expected and the verifier module in the CBAM Registry opens.
- Late 2026 and 2027. Verification engagements are contracted and site visits scheduled, in a market where accredited capacity is new and demand is concentrated.
- 1 February 2027. Sales of CBAM certificates begin through the central platform, covering 2026 imports. See our overview of how buying CBAM certificates will work.
- 30 September 2027. The annual CBAM declaration for 2026 imports is due, based on verified emissions, and certificates must be surrendered.
Verification capacity is the constraint that no individual importer controls. A limited pool of newly accredited verifiers will be asked to inspect installations across several continents within roughly twelve months. Companies that book late will be competing for the same weeks.
How importers should prepare
Nothing here requires waiting for an accredited verifier to exist. The preparatory work is entirely in your hands:
- Collect installation level data now. Verified emissions are tied to a specific production installation, not to a supplier or a trading company.
- Document the method. A verifier assesses how the figure was produced, including monitoring arrangements, measurement points and the treatment of precursors.
- Secure access rights. Add a clause obliging suppliers to permit a verifier site visit, and start that conversation with the suppliers who matter most by volume.
- Prioritise by exposure. Rank suppliers by embedded tonnes rather than by invoice value, and start with the ones that drive your certificate bill.
- Approach the market early. Indicative discussions with prospective verifiers cost nothing and reveal capacity constraints while there is still time to react.
CBAM Desk is built around this audit trail. Supplier data is captured per installation with its source and method, so what you hand to a verifier is a documented dataset rather than a reconstructed spreadsheet. Our partner network can help where specialist support on the ground is needed.
FAQ
When will the first accredited CBAM verifiers be available?
The European Commission expects the first CBAM verifiers to obtain accreditation around September 2026, which is also when the verifier module in the CBAM Registry opens. Until an accreditation is actually published, no verifier can sign off a CBAM declaration.
Who can act as a CBAM verifier?
Only legal entities accredited by a national accreditation body in the European Union, under Article 18 of the CBAM Regulation and Commission Delegated Regulation (EU) 2025/2551. Applicants may be established in the EU or in a third country, but the accreditation itself must come from an EU accreditation body.
Does a CBAM verifier have to visit the production site?
In the first year of verification, the verifier must carry out an on-site inspection of the installation where the goods are produced. Implementing Regulation (EU) 2025/2546 sets out the limited circumstances in which a virtual visit or a waiver is possible, and the verification report must record the details and the reasons.
When does verified emissions data first have to be submitted?
The annual CBAM declaration covering 2026 imports is due by 30 September 2027, and the embedded emissions it reports must be verified. That leaves roughly a year between the first accreditations and the first hard deadline.
What should importers do before verification capacity is available?
Collect installation level emissions data from suppliers now, document the calculation method and the monitoring arrangements, and agree with suppliers that a verifier may need site access. Verification confirms data that already exists; it cannot create it.
Key takeaway
Accredited CBAM verifiers arriving around September 2026 turn verification from a theoretical requirement into a scheduling problem with a fixed deadline of 30 September 2027. The importers who come through it comfortably will be the ones who spent late 2026 collecting installation level data and securing site access, not the ones who started looking for a verifier in the summer of 2027. Speak to our team about getting your supplier data verification ready.