Istanbul is served by two airports, Ataturk International on the European side and Sabiha Gökçen* on the Asian side.
Most major airlines fly into Ataturk International. Guests travelling from Europe & the UK may find budget airline service to Sabiha Gökçen.
Both airports have an excellent & very reasonable shuttle service to Taksim. Havaş takes approximately 40 minutes from Ataturk to Taksim Square for 10 Turkish Lira and approximately 90 minutes from Sabiha Gökçen to Taksim Square for 14 Turkish Lira, payable to the driver upon boarding. Travel times stated are subject to traffic.
Shuttle bus from Ataturk International to Taksim (2nd listing)
Shuttle bus from Sabiha Gökçen to Taksim (at bottom of page)
Depending on traffic, taxi fares from the airports, particularly Sabiha Gökçen, could run high. If you do choose to take a taxi, use a yellow taxi from the taxi rank. Many are equipped to take credit cards, otherwise be prepared to pay in Turkish Lira.
* Bit of trivia - Sabiha Gökçen, in the 1930’s, was the first female combat pilot.
Just before Passport Control at both airports there is signage directing you to the Visa counter. Simply hand them your passport and the appropriate fee for a multiple entry Visa stamp. As of 10 June 2011 the fee was £10.00, €15.00, $20.00(US).