FR 3977 then LA 5788 at Barcelona
Dublin → Barcelona → Santander
Timetable, Barcelona time
19:05FR 3977 from Dublin at the gate
16:05LA 5788 to Santander leaves the gate
21 h apart on the timetable, overnight
LA 5788 leaves 21 h after FR 3977 arrives on the timetable: more than half a day, so not a connection we count.