British Airways, Iberia, Finnair, American Airlines and various other airlines have round-trip flights from Seattle (SEA) to London, United Kingdom (LHR) for $615, NONSTOP. Flights January to May. Departures on Monday, Tuesday, Wednesday, and Sunday. 7-day minimum stay required.
We’ve previously mentioned cheaper flights on discount carriers to London that had a connection, but these are for NONSTOP AA/BA/Oneworld.