Unlike like Atatürk Airport, at Istanbul Airport there is more than one international lounge. Eligibility depends on your travel of class and your frequent flyer card status. PLEASE READ THIS WIKI BEFORE ASKING QUESTIONS.

For discussions and questions regarding outstation lounges ( Moscow, Nairobi, Washington DC ) and all other domestic lounges ( including SAW ) please refer to the respective forum.
For PriorityPass Lounges in Istanbul Airport (IST) please consult this thread in the Europe forum or the Istanbul Airport Master Thread for questions regarding contract lounges.

This thread covers TK Lounges at IST airport.

Chart of Eligibility for Lounges:



Thanks to DELLAS for sharing this chart.

International Lounges:
Miles&Smiles Lounge: This lounge is open to all Turkish Airlines Miles&Smiles Elite, Elite Plus card holders and Star Alliance Gold status holders along with one of their guests when flying Turkish Airlines or another Star Alliance member. Miles&Smiles Elite Plus members are also able to guest family members regardless of the number of people (spouse and children). Also Turkish Corporate Club members are allowed to access this lounge with one fellow guest who holds a valid boarding pass on Turkish Airlines.

To access this lounge take the elevators across gate C1 to the mezzanine level.

Business Lounge: This lounge would be open for all Business Class passengers on Turkish Airlines and Star Alliance partners. Unfortunately, no guests are allowed to this lounge.

To access this lounge take the elevators across gate E1 to the mezzanine level.

Both lounges are non-smoking. The nearest "terrace" (IST does not advertise smoking areas) is: For the business lounge: exit via the escalators, turn left and left again, past the public rest areas, and the terrace is on the right hand side. For the M&S lounge: exit via the escalators, turn right and right again, past the public rest areas, and the terrace is on the left hand side. In both cases a 3 minute walk.

Exclusive Lounge: No details, no plans as of yet
Arrivals Lounge: No details, no plans as of yet

Both the Business Lounge and the Miles&Smiles Lounge have showers, sleeping rooms and Turkish speciality food.

To use the sleeping rooms, you must have a connection time between 4h and 9h and the duration of one of your flights must be more than 8 hours. Unfortunately, Miles&Smiles Elite card holders and Star Alliance Gold card holders traveling in Economy Class are not eligible to use the sleeping room service. For sleeping room related issues please consult the this thread.

None of the international lounges have direct lounge access from the check-in hall; however, priority immigration and security checkpoint are available both for transfer passengers and passengers starting their journey in Istanbul.

Domestic Lounges:

The domestic lounge has two sections; one for Turkish Airlines Miles & Smiles Classic Plus and Elite card holders, Star Alliance Gold card holders and Turkish Corporate Club members (if they have a same day onward international connection); and the other one for Business Class passengers and Miles&Smiles Elite Plus card holders.

Miles&Smiles Elite passengers, Star Alliance Gold card holders and Turkish Corporate Club members can invite one guest into the lounge. Miles&Smiles Elite Plus passengers can also guest one passenger or their family members regardless of the number of people (spouse and children). Miles&Smiles Classic Plus card holders do not have the right to guest someone.

The lounge has a separate entrance and check-in lobby from the street, along with a special valet parking drop-off point. Transfer passengers and passengers who decide to use the main terminal building can also access this lounge by using the elevators across gates G6 and G7. Be aware that there are no lounge signs within the terminal so it's advised to follow signs for gates G6 and G7.