Same underlying idea, genuinely different mechanics — a certificate-purchase scheme in the EU, a direct tax in the UK, with separate deadlines and separate verification standards.
Last verified: 02 September 2026
Both regimes exist to stop imported goods with a lower embedded carbon price undercutting domestically-produced goods that already pay one — but the mechanics are genuinely different, not just a renamed copy of each other.
| EU CBAM | UK CBAM | |
|---|---|---|
| Mechanism | Certificate purchase & surrender | Direct tax (Finance Act 2026, Part 3) |
| Filed through | CBAM Registry, annual declaration | HMRC Self Assessment |
| Effective from | 1 January 2026 (definitive phase) | 1 January 2027 |
| First filing due | 30 September 2027 (2026 reporting year) | 31 May 2028 (2027 reporting year) |
| Verification standard | ISO 17029 accreditation | GACI accreditation scheme |
| Carbon-price-paid deduction | Article 9 | Carbon Price Relief (CPR) |
A company importing into both the EU and the UK doesn't get one combined deadline — each regime runs on its own calendar. EU CBAM's 2026 declaration is due 30 September 2027; UK CBAM's first-ever return (for the 2027 period, since the regime doesn't start until 1 January 2027) isn't due until 31 May 2028.
The same underlying production and emissions data can support both filings — a shared installation's Specific Embedded Emissions figure doesn't need to be calculated twice — but the filing mechanics, evidence format, and deadlines are handled entirely separately.
An ISO 17029-accredited verification prepared for an EU CBAM declaration doesn't automatically satisfy UK CBAM's GACI accreditation requirement, and vice versa. If you're compliant in both jurisdictions, budget for two separate verification relationships — or one verifier accredited under both schemes, where available.
Read the full UK CBAM breakdown on our dedicated UK CBAM page.
No. They share the same underlying goal (pricing embedded carbon in imports) but are structurally different: EU CBAM is a certificate purchase-and-surrender scheme; UK CBAM (Finance Act 2026, Part 3) is a direct tax filed through HMRC Self Assessment.