A common tip says it is enough to check whether the barcode starts with 84. It is not: 84 means the company registered with GS1 Spain, not that the product was made there.
What does work
Look for “Hecho en España”, “Fabricado en España”, “Origen: España” or “Made in Spain”. Fresh meat, fresh fruit and vegetables, unprocessed fish, eggs, honey and virgin and extra virgin olive oil must state their origin in the EU.
Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) labels guarantee a regulated link to an area: with PDO the whole process happens there; with PGI, at least one stage.
Scan the barcode with Origen: you will see the manufacturing country and ingredient origins, with their flags, when the public record states them.
Common traps
“Packed in Spain” or “Distributed by” a Spanish company does not mean the product was made there.
A Spanish flag on the pack does not replace the origin statement. If the product is not Spanish, the law requires saying so when the image could mislead.
Supermarket brands based in Spain may manufacture abroad. Check the manufacturer or the country of origin, not just the brand.
Example records that declare where the product is made