Athens is 7 hours ahead of Ottawa
Best overlap: 8:00 AM to 11:00 AM in Ottawa is 3:00 PM to 6:00 PM in Athens.
If you set up a recurring sync, 8:00 AM to 11:00 AM in Ottawa (3:00 PM to 6:00 PM in Athens) is the natural home for it. Athens is 7 hours ahead of Ottawa, leaving about 3 hours of daily overlap — enough for most meetings if you don't leave them too late in the day.