Are there nonstop flights from London (STN) to Seattle (SEA)?

No. The fastest connection is via Reykjavík, about 10h 3m of total flying time.

What is the fastest connection from London (STN) to Seattle (SEA)?

via Reykjavík ≈ 10h 3m, via Dublin ≈ 10h 7m, via Amsterdam ≈ 10h 35m (estimated flying time, excluding layovers).

from 27,500 ANA miles (economy, one way, based on the published award charts).

London Stansted Airport (STN) to Seattle–Tacoma International Airport (SEA)・7,695 km

No nonstop flights. The fastest connection is via Reykjavík (KEF), about 10h 3m of flying time (layover not included).

With milesANA 27,500 miles+ (via MUC)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.