Residency permit through real estate purchase is quite straightforward. If citizenship application will not be the case, there is no minimum investment requirement. The only required check is with the title of the property for eligibility for foreign ownership (should be checked from the local title registry office since some zones are reserved for military and some others may not be suitable for other reasons). The stages are simple, enter into Turkey with a valid visa or exemption, check and purchase a property, apply for residence permit. The whole process may take one to three months to finalize.
