GQ 681 then GQ 430 at Athens
Sofia → Athens → Skiathos
Timetable, Athens time
21:55GQ 681 from Sofia at the gate
13:30GQ 430 to Skiathos leaves the gate
15 h 35 apart on the timetable, overnight
GQ 430 leaves 15 h 35 after GQ 681 arrives on the timetable: more than half a day, so not a connection we count.