GSM Services and Simcards in Turkey
There are three GSM providers in Turkey that can set you up with a simcard and GSM plan. Turkcell, Vodafone, and Turk Telekom are the three operators, and all have a good coverage in Turkey. They all offer GSM plans with different amounts of call and internet/data use. According to Turkish law, all simcards must be registered, and can only be purchased with a valid passport.