The Great Move is Beginning! The relocation operation from Istanbul Atatürk Airport to Istanbul Airport will be carried out between 5 April 2019 3:00 a.m. and 7 April 2019 12:00 midnight (GMT + 3). Our passengers should contact the relevant airlines company for details about their flight.
Here is the Official site;
How to reach New Istanbul Airport
Airport Buses - HavaIst
İstanbul Otobüs A. Ş., a company associated with the Istanbul Metropolitan Municipality, operates an airport bus service named Havaİst serving the new Istanbul Airport.
The bus service is currently scheduled to serve the limited number of flights using the airport. Frequency of service will be increased as flights to the new airport increase.
Taxis or Private Istanbul Airport Transfer Services will be two main alternative modes of transport for Istanbul Airport .
Istanbul Airport Transfer Services starting from 50 USD per way.