3.Transitional period (history) and definitive period (now)

	Transitional (ended)	Definitive (now)
Period	1 Oct 2023 to 31 Dec 2025	from 1 Jan 2026
Who reports	importer or indirect customs representative	authorised CBAM declarant
Frequency	quarterly report	annual CBAM declaration
Verification	not required	required when actual emissions are used
Payment	none	buy and surrender CBAM certificates

The transitional period was reporting only. Treat its templates, factsheets and advice with care.

In the definitive period the core obligations apply from 1 January 2026. Two pieces start later: the quarterly holding rule (1 January 2027) and certificate sales (1 February 2027). This course uses the consolidated CBAM Regulation of 20 October 2025, including the 2025 simplification amendments.

Sources: REG Art 6, 8, 22, 32, 36(2); REG-AMD; TP-IR; G1 Table 2-1 p.9, Table 2-2 p.10-11.