I am living in Turkey for three years now and I travelled the complete Turkish coast between Iskenderun und Izmir meanwhile.
Unfortunately I have not really good news for you.
Incirlik is close to the Turkish city of Adana. Although Adana is quite close to the Mediterranean coast, this is not a diving area. I dont know if the US Forces offer some diving opportunities. Otherwise chances are not very good. In that area the dive sites are quite poor and also you would not find any international standard dive centre.
The region where you will find diving in Turkey starts at Alanya and goes along the coast northward to Canakkale.
But the region between Alanya and Antalya I can not recommend as well. In that area the dive sites are quite poor as well. Good dive sites you will find north of Antalya. In Antalya city there is an interesting dive site as well. Directly at the old harbour there is the wreck of a French freighter from the time of WW II. There is also a local dive centre direct in the old harbour. They speak English as well and with their RIP its a 5 minute trip to the wreck.
Probably the best dive sites in Turkey you will find in the small village of Kas, a bit north of Antalya. The second best dive sites you will find in the region of Bodrum in the Aegean Sea. Also very interesting is the area of Ayvalik and last but not least Canakkale, both in the North Aegean Sea.
If you have any specific questions, feel free to contact me.