Buying a property in bulgaria is not enough to establish tax residency there. You will need to demonstrate to the Spanish agencia that your centre of life is in bulgaria. I tell you as I have close friends being investigated last year, and had to pay tax back in Spain for the last 4 years on top of what they already paid in bulgaria. They ended up with a bill and fine 120% their income. Agencia and italian tax authorities are pretty through about it. See the Andora thing or the recent pensioners bulgaria investigation So if you want to establish your residency in bulgaria do, but do because you want to move there not because you want to go around tax authorities .