Generally, the answer is yes unless a double tax treaty provides protection. Spain tax treaties, specially the most recently signed ones, follow OECD guidelines and grant taxing rights to the country where the real estate is situated (Spain, in our case) even if transferring the shares of an entity, whether Spanish or not. In the absence of an appropriate tax treaty, Spain tax rules also provide for taxation on the transfer of shares of entities whose assets mainly consist of Spanish real estate. Capital gains (if any, nowadays...) of non-residents are currently taxed at a rate of 21%.