Tehran is 3.5 hours ahead of Reykjavik
Best overlap: 8:30 AM to 2:30 PM in Reykjavik is 12:00 PM to 6:00 PM in Tehran.
The hours that work for both Reykjavik and Tehran are 8:30 AM to 2:30 PM (Reykjavik) and 12:00 PM to 6:00 PM (Tehran). Plenty of room to work with: 6 hours of daily overlap means you can prioritise people's preferences over the clock.