Are there nonstop flights from Osaka (KIX) to Bandar Seri Begawan (BWN)?

No. The fastest connection is via Manila, about 5h 35m of total flying time.

What is the fastest connection from Osaka (KIX) to Bandar Seri Begawan (BWN)?

via Manila ≈ 5h 35m, via Taipei ≈ 5h 45m, via Hangzhou ≈ 6h 6m (estimated flying time, excluding layovers).

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

Kansai International Airport (KIX) to Brunei International Airport (BWN)・3,889 km

No nonstop flights. The fastest connection is via Manila (MNL), about 5h 35m of flying time (layover not included).

With milesANA 19,000 miles+ (via SZX)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

11 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.