Are there nonstop flights from Ulaanbaatar (UBN) to Haikou (HAK)?

No. The fastest connection is via Ordos, about 4h 40m of total flying time.

What is the fastest connection from Ulaanbaatar (UBN) to Haikou (HAK)?

via Ordos ≈ 4h 40m, via Hohhot ≈ 4h 44m, via Guangzhou ≈ 4h 49m (estimated flying time, excluding layovers).

from 18,000 ANA miles (economy, one way, based on the published award charts).

Ulaanbaatar Chinggis Khaan International Airport (UBN) to Haikou Meilan International Airport (HAK)・3,099 km

No nonstop flights. The fastest connection is via Ordos (DSN), about 4h 40m of flying time (layover not included).

With milesANA 18,000 miles+ (via HET)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

16 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.