A3 981 then GQ 342 at Athens
Sofia → Athens → Santorini
Timetable, Athens time
12:20A3 981 from Sofia at the gate
11:50GQ 342 to Santorini leaves the gate
23 h 30 apart on the timetable, overnight
GQ 342 leaves 23 h 30 after A3 981 arrives on the timetable: more than half a day, so not a connection we count.