Where to find it
On a TIE card it starts with the letter E followed by digits (e.g. E00000000) and is printed on the front or back of the card.
On the green EU certificate it is the IXESP / C-number reference. On older A4 certificates it may be labelled "Nº de soporte" near the top.
What it is used for
It is required to verify your identity on digital services such as Cl@ve, the immigration portal, and many regional administration websites. Without it, online procedures cannot be completed.
In Bilbao
Sorting the número de soporte in Bilbao means dealing with Oficina de Extranjería de Bizkaia and its limited appointments. We monitor the system daily and handle the paperwork for residents from Santurtzi and Barakaldo.