FR 1644 then OS 439 at Vienna
Rome → Vienna → Bilbao
Timetable, Vienna time
21:30FR 1644 from Rome at the gate
15:05OS 439 to Bilbao leaves the gate
17 h 35 apart on the timetable, overnight
OS 439 leaves 17 h 35 after FR 1644 arrives on the timetable: more than half a day, so not a connection we count.