Are there nonstop flights from Osaka (KIX) to Ulaanbaatar (UBN)?

Yes. MIAT Mongolian Airlines fly this route. Flight time is about 3h 46m.

What is the fastest connection from Osaka (KIX) to Ulaanbaatar (UBN)?

via Seoul ≈ 4h 19m, via Cheongju ≈ 4h 20m, via Daegu ≈ 4h 21m (estimated flying time, excluding layovers).

from 15,000 JAL miles, from 19,000 ANA miles (economy, one way, based on the published award charts).

Kansai International Airport (KIX) to Ulaanbaatar Chinggis Khaan International Airport (UBN)・2,777 km

Nonstop flights available (1 airline). Flight time about 3h 46m. Nonstop return flights also operate.

With milesJAL 15,000 miles+ (via ICN)ANA 19,000 miles+ (via ICN)Economy, one way, estimate. Tap a connection for miles by cabin.

12 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.