Register the escritura at the Land Registry (Registro de la Propiedad) — technically voluntary in Spain (mandatory only if you take a mortgage), but strongly recommended: it puts your title under court protection

The title says the quiet part: registration at the Registro de la Propiedad is technically voluntary — and you should absolutely do it anyway. Registration is what makes your ownership visible to and defensible against third parties. Usually your notary or gestoría files it as part of completion; confirm rather than assume.