Flight Kansai International Airport departs from Osaka Kansai International Airport at 09:30 and arrives at Ho Chi Minh City Tan Son Nhat International Airport at 13:00.
The flighttime is about 5h 30m. The distance travelled ("as the bird flies"): 3399 Km. So the average speed is roughly 618 Km.
There is an 2 hour time difference between Osaka and Ho Chi Minh City