Flight Phnom Penh International Airport departs from Phnom Penh Phnom Penh International Airport at 19:05 and arrives at Hong Kong Hong Kong International Airport at 22:35.
The flighttime is about 2h 30m. The distance travelled ("as the bird flies"): 1080 Km. So the average speed is roughly 432 Km.
There is an 1 hour time difference between Phnom Penh and Hong Kong