Istanbul is 1 hour ahead of Barcelona

Best overlap: 8:00 AM to 5:00 PM in Barcelona is 9:00 AM to 6:00 PM in Istanbul.

For the smoothest call, aim inside 8:00 AM to 5:00 PM in Barcelona, i.e. 9:00 AM to 6:00 PM in Istanbul. This is one of the easier pairings: 9 hours of shared time means flexible, low-stress scheduling. Note that Barcelona follows daylight saving while Istanbul stays put, so the times above drift by an hour seasonally.