Buying or selling a property on the Costa del Sol as a non-tax resident involves complying with several essential legal and tax procedures: obtaining a NIE, paying local taxes (ITP transfer tax, VAT, or municipal plusvalía), and signing the public deed of sale before a notary. However, an administrative obligation often goes unnoticed and is vital to understand to avoid penalties: the declaration before the Foreign Investment Registry (Registro de Inversiones Exteriores - RIE