A3 981 then TK 1848 at Athens
Sofia → Athens → Istanbul
Timetable, Athens time
13:00A3 981 from Sofia at the gate
06:55TK 1848 to Istanbul leaves the gate
17 h 55 apart on the timetable, overnight
TK 1848 leaves 17 h 55 after A3 981 arrives on the timetable: more than half a day, so not a connection we count.