Are there nonstop flights from Seattle (SEA) to Haikou (HAK)?

Yes. Hainan Airlines fly this route. Flight time is about 13h 17m.

What is the fastest connection from Seattle (SEA) to Haikou (HAK)?

via Seoul ≈ 13h 47m, via Shanghai ≈ 13h 48m, via Hong Kong ≈ 13h 48m (estimated flying time, excluding layovers).

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

Seattle–Tacoma International Airport (SEA) to Haikou Meilan International Airport (HAK)・10,860 km

Nonstop flights available (1 airline). Flight time about 13h 17m. Nonstop return flights also operate.

With milesJAL 45,000 miles+ (via HKG)Economy, one way, estimate. Tap a connection for miles by cabin.

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.