A3 275 then GQ 342 at Athens
Chios → Athens → Santorini
Timetable, Athens time
17:00A3 275 from Chios at the gate
11:50GQ 342 to Santorini leaves the gate
18 h 50 apart on the timetable, overnight
GQ 342 leaves 18 h 50 after A3 275 arrives on the timetable: more than half a day, so not a connection we count.