UK CBAM Checklist 2027: What to Do Before January 2027

CBAM begins on 1 January 2027. The businesses that start preparing in 2026 will be ready. Those who leave it until 2027 will face rushed supplier conversations, incomplete data, and higher default-value CBAM costs. Start now.

Your preparation checklist: Identify all your imported goods and map them to 8-digit CN codes. Cross-reference each code against the HMRC list of CBAM-covered codes. Calculate your approximate annual CIF value of CBAM-covered imports to determine whether you exceed the £50,000 threshold. If you are close to or above the threshold, identify every supplier of CBAM-covered goods and prepare to contact them for emissions data.

Set up your record-keeping systems before CBAM starts. Decide whether you will manage CBAM data in spreadsheets, a dedicated system like Oremly, or a combination. The key requirement is that every figure in every return must be backed by a source document retained for six years. Design your system around that requirement, not around convenience.

From January 2027, every shipment of CBAM-covered goods must have its emissions tracked and recorded. Your first return covers the full 2027 calendar year and is due by 31 January 2028.

Your first-year checklist: Monitor your cumulative import value monthly to track whether you are approaching the £50,000 threshold. If you exceed it, register with HMRC within 30 days. Send CBAM data requests to all suppliers of covered goods. Set a 30-day response expectation and follow up at 60 days. For any supplier that does not respond, document your efforts and prepare to use default values. Track every CBAM-covered shipment with its net weight, CN code, and emissions data.

Build your emissions data for each product. Where you have verified supplier data, store the verification certificate. Where you have unverified data, store the source email or document. Where you use defaults, record which default value and why. At the end of 2027, compile your return, calculate your CBAM liability, and file by 31 January 2028.

1 January 2027: CBAM comes into effect. Start tracking all CBAM-covered imports from this date. 30 days after exceeding £50,000: Registration deadline. Monitor your cumulative import values throughout the year. 31 January 2028: First CBAM return due (covering 2027). File your return and pay any liability. 1 January 2028 onwards: CBAM continues. Second year of annual returns begins.

January 2029 at the earliest: Transition from annual to quarterly returns (exact date TBC by HMRC). Quarterly returns are more demanding — four returns per year instead of one — so use the annual years to establish efficient data collection processes.

Throughout: HMRC may announce changes to covered goods, default values, or rate methodology. Monitor HMRC announcements, subscribe to the Oremly newsletter for UK CBAM updates, and adjust your processes as the regime evolves.

After your first return is filed, CBAM becomes a permanent compliance obligation. Your ongoing checklist: Request fresh supplier data at least 60 days before each return deadline. Update your import ledger with each new shipment. Reconcile your ledger against supplier data monthly. Calculate your CBAM liability quarterly (even during the annual return phase, to avoid year-end surprises). Review HMRC announcements for new default values, rate changes, or code additions. Maintain your evidence store with every new document. Update your registration if your business details change.

Oremly automates every item on this checklist. Import ledger auto-sync, automatic supplier data requests with follow-ups, AI extraction of emissions data from supplier documents, real-time CBAM liability dashboard, and HMRC field-order return summaries. Our users submit their first return in under an hour because the system has been tracking and calculating all year.