Are there nonstop flights from Seattle (SEA) to Shenzhen (SZX)?

No. The fastest connection is via Seoul, about 13h 15m of total flying time.

What is the fastest connection from Seattle (SEA) to Shenzhen (SZX)?

via Seoul ≈ 13h 15m, via Shanghai ≈ 13h 16m, via Vancouver ≈ 13h 17m (estimated flying time, excluding layovers).

from 22,500 ANA miles, from 45,000 JAL miles (economy, one way, based on the published award charts).

Seattle–Tacoma International Airport (SEA) to Shenzhen Bao'an International Airport (SZX)・10,418 km

No nonstop flights. The fastest connection is via Seoul (ICN), about 13h 15m of flying time (layover not included).

With milesANA 22,500 miles+ (via HND)JAL 45,000 miles+ (via ICN)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

20 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.