Resource
The UK CBAM deadlines, 2027 to 2028, as a calendar file
Law as at 13 September 2026.
The file holds the eight dates below as all-day events, each with the provision it rests on in its description. Every date comes from an instrument that has been made; none rests on a draft notice. The dates guide explains each date and the ordinary quarterly rule that applies from the quarter ending 30 September 2028.
| Date | What happens | Basis |
|---|---|---|
| 1 January 2027 | The tax starts, and the registration clock starts. | Section 158(1) of the Finance Act 2026; Schedule 17, paragraph 2(2). |
| 1 February 2027 | The first day on which the look-back registration test can be met, since goods imported in 2026 do not count. | Schedule 17, paragraph 2(2)(a). |
| 31 December 2027 | The end of the first accounting period, which is the whole of 2027. | SI 2026/830, regulation 2(3). |
| 31 January 2028 | The registration deadline for anyone who triggered registration in 2027. | SI 2026/830, regulation 2(2). |
| 31 May 2028 | The first return and payment, for the period to 31 December 2027, are due before the end of this day. | SI 2026/830, regulation 2(3) and (4). |
| 31 July 2028 | The return and payment for the quarter to 31 March 2028 are due before the end of this day. | SI 2026/830, regulation 2(3) and (4). |
| 29 September 2028 | The return and payment for the quarter to 30 June 2028 are due before the end of this day. | SI 2026/830, regulation 2(3) and (4). |
| 29 November 2028 | The return and payment for the quarter to 30 September 2028 are due before the end of the last working day of November, which is the Wednesday because 30 November is a bank holiday in Scotland. | Schedule 17, paragraphs 6(3) and 7(2); section 155(1); Banking and Financial Dealings Act 1971, Schedule 1, paragraph 2. |
A business that triggers registration in 2028 or later has thirty days from the trigger rather than the 31 January 2028 date, and its own trigger date is the one to add. A date that a later instrument moves will be changed in a new version of the file, with a new date line.