Istanbul is 1 hour ahead of Madrid

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

For a call that suits both sides, look at 8:00 AM to 5:00 PM in Madrid / 9:00 AM to 6:00 PM in Istanbul. Despite the 1-hour difference, a 9-hour overlap keeps things simple and gives both teams breathing room. Finally, Madrid observes daylight saving and Istanbul doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.