Flight Sydney Airport departs from Sydney Sydney Airport at 10:15 and arrives at Ho Chi Minh City Tan Son Nhat International Airport at 16:30.
The flighttime is about 9h 15m. The distance travelled ("as the bird flies"): 5581 Km. So the average speed is roughly 603 Km.
There is an 3 hour time difference between Sydney and Ho Chi Minh City