My family and I are traveling to Dubai via Istanbul from Abuja, Nigeria. The layover is 12 hours. We have 2 little children, 1 infant and a senior in our party, all on Nigerian passports. I want to know if we require a transit visa and whether the facilities in the transit area good enough to stay there 12 hours if we decide to. We are flying Turkish Airlines.
No, you don't need a transit visa as long as you stay in the international area, according to Turkey's e-visa portal
Do I have to obtain a visa if I do not leave the international transit area?
No. You do not have to get a visa if you are not going to leave the international transit area.
More of the same from the Turkish Ministry of Foreign Affairs
Question: I will be flying to Europe. I know that our aircraft will land in İstanbul. I am not planning to leave the transit lounge. Do I need to get transit visa?
Answer: If you will not leave the transit lounge at the airport you are not required to have transit visa. Otherwise, you have to make visa application to the nearest Turkish Representation. Contact information of the said missions can be reached through www.mfa.gov.tr (Ministry/Turkish Representations).