Are there nonstop flights from Seattle (SEA) to Manchester (MHT)?

No. The fastest connection is via Chicago, about 5h 51m of total flying time.

What is the fastest connection from Seattle (SEA) to Manchester (MHT)?

via Chicago ≈ 5h 51m, via Chicago ≈ 5h 51m, via Philadelphia ≈ 6h 3m (estimated flying time, excluding layovers).

from 23,000 JAL miles (economy, one way, based on the published award charts).

Seattle–Tacoma International Airport (SEA) to Manchester-Boston Regional Airport (MHT)・3,946 km

No nonstop flights. The fastest connection is via Chicago (ORD), about 5h 51m of flying time (layover not included).

With milesJAL 23,000 miles+ (via CLT)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

13 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.