Supplementary Declaration (SDI)
A Supplementary Declaration is a type of customs declaration submitted after goods have already been released using a simplified procedure, such as Simplified Customs Declaration Procedures (SCDP) or Entry in Declarant’s Records (EIDR).
Under these procedures, only limited information is provided at the time of import (or recorded in the trader’s own systems), allowing goods to move more quickly across the border. The Supplementary Declaration is then submitted later to provide the complete and final details of the goods, including their value, classification, origin, and any duties or VAT due.
For SCDP (e.g. Simplified Frontier Declarations), the Supplementary Declaration finalises the initial reduced data declaration submitted at the border.
For EIDR, it follows the entry made in the trader’s own records, which replaces the need for a frontier declaration altogether.
Supplementary Declarations must be submitted within set timeframes and are essential for ensuring that the customs procedure is properly completed and that all liabilities are correctly accounted for.