Are there nonstop flights from Sapporo (CTS) to Doha (DOH)?

No. The fastest connection is via Seoul, about 10h 58m of total flying time.

What is the fastest connection from Sapporo (CTS) to Doha (DOH)?

via Seoul ≈ 10h 58m, via Shanghai ≈ 11h 34m, via Osaka ≈ 11h 34m (estimated flying time, excluding layovers).

from 20,000 JAL miles (economy, one way, based on the published award charts).

New Chitose Airport (CTS) to Hamad International Airport (DOH)・8,140 km

No nonstop flights. The fastest connection is via Seoul (ICN), about 10h 58m of flying time (layover not included).

With milesJAL 20,000 miles+ (via HND)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

10 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.