Are there nonstop flights from Singapore (SIN) to Ulaanbaatar (UBN)?

Yes. MIAT Mongolian Airlines fly this route. Flight time is about 6h 34m.

What is the fastest connection from Singapore (SIN) to Ulaanbaatar (UBN)?

via Ho Chi Minh City ≈ 7h 6m, via Sanya ≈ 7h 10m, via Nha Trang ≈ 7h 13m (estimated flying time, excluding layovers).

from 15,000 ANA miles, from 37,000 JAL miles (economy, one way, based on the published award charts).

Singapore Changi Airport (SIN) to Ulaanbaatar Chinggis Khaan International Airport (UBN)・5,155 km

Nonstop flights available (1 airline). Flight time about 6h 34m. Nonstop return flights also operate.

With milesANA 15,000 miles+ (via PEK)JAL 37,000 miles+ (via ICN)Economy, one way, estimate. Tap a connection for miles by cabin.

17 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.