Are there nonstop flights from Busan (PUS) to Siem Reap (SAI)?

No. The fastest connection is via Da Nang, about 5h 6m of total flying time.

What is the fastest connection from Busan (PUS) to Siem Reap (SAI)?

via Da Nang ≈ 5h 6m, via Hanoi ≈ 5h 16m, via Ho Chi Minh City ≈ 5h 36m (estimated flying time, excluding layovers).

from 18,500 ANA miles (economy, one way, based on the published award charts).

Gimhae International Airport (PUS) to Siem Reap-Angkor International Airport (SAI)・3,467 km

No nonstop flights. The fastest connection is via Da Nang (DAD), about 5h 6m of flying time (layover not included).

With milesANA 18,500 miles+ (via SIN)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

6 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.