CBAM is, underneath the regulation, a documentation problem. Every figure you eventually declare has to be traceable to a source, and the records behind it accrue all year — long before the declaration is due. This is a practical checklist for the evidence to keep and how to organise it, so the work at deadline is review rather than reconstruction.
Why build the file during the year
Your first annual CBAM declaration covers 2026 imports and is due 30 September 2027 (full timeline). If the evidence is captured as shipments happen, the declaration is an act of compiling. If it is not, you spend the run-up to the deadline searching inboxes and shared drives for a year of documents — which is when mistakes and expensive default-value fallbacks happen.
The evidence checklist
Per covered shipment
- Commercial invoice
- Customs declaration / import entry
- Packing list and transport documents
- Product description and the CN code used
- The in-scope decision and its reasoning (why CN codes matter)
Supplier and emissions data
- The emissions-data request you sent, and the date
- Reminders and follow-ups sent
- The supplier’s response (or a logged non-response)
- Embedded-emissions figures: direct, indirect, production route
- Basis of the data (measured / calculated / estimated) and any verification
- Where a default value was used, a note of why (supplier data process)
Reconciliation and declaration prep
- A shipment register tying all of the above together
- A missing-field log: what is still outstanding, by supplier and shipment
- Assumptions made, recorded explicitly
- A clear separation of confirmed information from open questions
Organise for review, not just storage
Keeping the documents is not the same as keeping them usable. A few principles:
- One shipment, one trail. Everything about a consignment should be findable together, not scattered by document type across inboxes.
- Decisions are evidence too. A reasoned note (“supplier did not respond after three requests; default value applied”) is as important as the invoice.
- Make gaps visible. The unresolved items should be a list someone can act on, not a silence no one notices.
- Write for the reviewer. Your customs broker, adviser, or auditor should be able to follow the file without you in the room.
Where CarbonBorder Desk fits
This checklist is essentially our deliverable. We build the shipment register, run the supplier data chasing, maintain the missing-field log, and keep the whole archive structured so it can be reviewed and signed off. We do not file declarations or give legal opinions — we make the evidence behind them clean and traceable. A pilot diagnostic produces a working version of this file for one of your import flows.