In Turkey we have 3 main GSM Operators. They are;
You have to register your mobile phones to those GSM operators in 30 days, after your arrival to Turkey.Otherwise, your phone will be blocked. In order to register your phone, You should need the documents below:
1) The document that shows you are a student (You’ll get it from the University)
2) Passport (Original Copy)
For more Information; Please visit the page of Information Technologies and Communication Association www.tk.gov.tr .