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