I am travelling to Romania with Turkish airlines with a 10 hour layover in Istanbul. I have a valid Romanian visa, am I eligible to get a Turkish e-visa? The conditions on the e-visa website are confusing. Romania is part of the EU but not a full-fledged Schengen state.
If you go through the application for the Turkish E Visa you will get to the prerequisites page.
So if you hold a Schengen visa or an OECD country visa you are eligible to have one.
Romania as of this time is not a party to either one of these agreements so to get a eVisa you will need to have a visa for another country that is a party to one of these agreements. Save that obtain a regular visa or stay at the airport for which you're not required to have a visa.