Flight Tan Son Nhat International Airport departs from Ho Chi Minh City Tan Son Nhat International Airport at 19:55 and arrives at Sydney Sydney Airport at 07:20.
The flighttime is about 8h 25m. The distance travelled ("as the bird flies"): 5581 Km. So the average speed is roughly 663 Km.
There is an 3 hour time difference between Ho Chi Minh City and Sydney