Reykjavik is 1 hour behind Zurich
Best overlap: 9:00 AM to 6:00 PM in Zurich is 8:00 AM to 5:00 PM in Reykjavik.
For a call that suits both sides, look at 9:00 AM to 6:00 PM in Zurich / 8:00 AM to 5:00 PM in Reykjavik. Because you share 9 hours of the workday, there's no need to compromise; book the time that suits the meeting, not the map. Finally, Zurich observes daylight saving and Reykjavik doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.