Islamabad is 2 hours behind Hanoi
Best overlap: 10:00 AM to 6:00 PM in Hanoi is 8:00 AM to 4:00 PM in Islamabad.
Schedule calls for 10:00 AM to 6:00 PM in Hanoi — your colleagues in Islamabad will be online from 8:00 AM to 4:00 PM. With 8 hours of daily overlap, these two cities are an easy pairing; almost any reasonable hour works.