Flight Tan Son Nhat International Airport departs from Ho Chi Minh City Tan Son Nhat International Airport at 12:20 and arrives at Seoul Incheon International Airport at 19:25.
The flighttime is about 5h 05m. The distance travelled ("as the bird flies"): 2519 Km. So the average speed is roughly 496 Km.
There is an 2 hour time difference between Ho Chi Minh City and Seoul