Sydney is 3-4 hours ahead of Ho Chi Minh City. Ho Chi Minh City uses Indochina Time (ICT, UTC+7) while Sydney uses Australian Eastern Standard/Daylight Time (AEST/AEDT, UTC+10/+11). During standard time, Sydney is 3 hours ahead; during daylight saving time, Sydney is 4 hours ahead.
Sydney observes daylight saving time while Ho Chi Minh City does not, so the difference varies seasonally.
Best calling time: 6:00 AM - 3:00 PM Ho Chi Minh City time. This corresponds to approximately 9:00 AM - 6:00 PM in Sydney, depending on the season.
Ho Chi Minh City and Sydney have growing business and tourism connections. Australia has a significant Vietnamese diaspora, and there are direct flights between the cities taking about 8 hours.