The UK government has extended the first UK REACH transitional registration deadline from 27 October 2026 to 27 October 2029. The REACH (Amendment) (No. 2) Regulations 2026 (SI 2026/849) came into force on 6 August 2026. They also moved the second and third deadlines to 27 October 2030 and 27 October 2031. The extension changes submission dates, but the underlying obligations remain: Downstream User Import Notification (DUIN) holders still need a full registration to keep importing into Great Britain. Safety data sheet duties apply now. The one tonne per year threshold is unchanged. A compliant dossier still requires substance identity work, SIEF data access, cost-sharing agreements and supplier coordination, which can take years to complete. This guide explains: What changed under SI 2026/849, and which substances fall into each batch. Who is affected. A risk-prioritised plan for re-baselining your GB substance inventory, reconciling DUINs and confirming EU supplier registration
