The private Havataş
bus service provides rings between the airport and Taksim. The trip takes between 40 and 90 minutes, depending upon traffic, and costs from Sabiha Gokcen Airport 14TL, Ataturk Airport 11TL per person, one-way, payable on the bus in cash.
Sabiha Gokcen Airport to Taksim: 90 minutes, Fee 14TL per person
Ataturk Airport to Taksim: 40 minutes, Fee 11TL per person
If your airport is Ataturk, you can use the Metro line to reach Taksim. First hop on the metro in the airport (underground) in the direction of Yenikapi (M1A). The final destination of the metro, you must get off and take the M2 Yenikapi-Haciosman metro line. The next stop is Taksim Square.
Offical Istanbul Railway Network Map: Click here for high resolution image
Note: If you prefer to use public transport, every transfer requires you to buy a token or use pre-paid card “Istanbul Kart”, on average 2TL each and per person