You are required to register your mobile phones brought from your home country within 1 month after you enter Türkiye. You must apply to the Subscriber Registration Centers of the GSM Operators you are using in Türkiye with the necessary documents. Otherwise, your phone will be blocked and cannot be used. For application ; 1) Student Certificate (to be obtained from school) 2) Passport (Original) For detailed information; Information and Communication Technologies Authority, www.tk.gov.tr click this link.