Do I need a digital certificate for the Modelo 210?

That depends on the filing route. For direct filing through the AEAT's Sede Electrónica, a Spanish digital certificate (Certificado Digital) or Cl@ve PIN is generally required. Both serve as electronic identification with the AEAT. Obtaining either is typically cumbersome for non-residents without a Spanish address — the Certificado Digital is issued by the FNMT (Fábrica Nacional de Moneda y Timbre) and requires in-person identification. When filing through specialised platforms such as Fiscaro, a digital certificate is generally not required. Filing takes place through the designated submission process, with identification via the NIE number and the data captured in the wizard. When engaging a Gestor or Asesor Fiscal, the certificate is likewise unnecessary — the Gestor typically files using their own certificate or access credentials. For most non-residents, filing through a specialised platform or a Gestor is the most practical way to avoid the digital certificate hurdle.