GQ 681 then A3 992 at Athens
Sofia → Athens → Istanbul
Timetable, Athens time
21:55GQ 681 from Sofia at the gate
13:10A3 992 to Istanbul leaves the gate
15 h 15 apart on the timetable, overnight
A3 992 leaves 15 h 15 after GQ 681 arrives on the timetable: more than half a day, so not a connection we count.