A3 712 then LA 5794 at Barcelona
Athens → Barcelona → Vigo
Timetable, Barcelona time
18:45A3 712 from Athens at the gate
18:15LA 5794 to Vigo leaves the gate
23 h 30 apart on the timetable, overnight
LA 5794 leaves 23 h 30 after A3 712 arrives on the timetable: more than half a day, so not a connection we count.