Shippers of goods to Northern Ireland & the European Union must register with HMRC for an EORI number. This number is required for registration for shipment of goods to Northern Ireland via the Trader Support Service (below).
This number is assigned to importers/exporters by HMRC and is used during the customs clearance process. The Government have already contacted all UK VAT registered businesses outlining the requirements for shippers. EORI is linked to a VAT deferment account.
You will need to ensure you have an additional EORI number beginning with "XI" to be able to ship goods to Northern Ireland. To get an EORI number that starts with XI, you must already have an EORI number that starts with "GB".