Yes, once you have acquired property, you will have to declare it to the tax authorities and you will have many difficulties if you do not use an accountant. Practically, you will not be able to keep your Greek tax affairs in order without a local accountant. As long as you can prove that you didn’t earn the money to purchase the property in Greece, you will not be liable for income tax. Your tax declaration is made the year after the year in which you purchase your property.