Cheapest Day to Buy Flights from Seattle to London
Seattle to London is 7,702 km (4,786 mi) great-circle — commonly 8–12 h nonstop or with 1 stop. Fares typically bottom out 3–12 weeks before departure; the calendar below shows the cheapest price for every day of the next 12 months.
Check live prices on Aviasales ↗Low Fare Calendar — Seattle to London
When to book vs. when to fly — Seattle → London
Live data from recent Aviasales searches for SEA → LHR, plus a booking rule of thumb.
Lowest indicative per-adult round-trip fares seen in Aviasales searches — confirmed live on the booking site before payment.
See the cheapest month’s fares ↗Search any date — Seattle → London
Flight options — Seattle → London
Recently-seen round-trip fares — click any flight for details, alternatives and booking.
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FAQ — SEA → LHR
How much is a flight from Seattle to London?
Prices vary by season and departure day. The Low Fare Calendar on this page shows the cheapest fare for every day of the coming year between Seattle (SEA) and London (LHR).
Which airlines fly from Seattle to London?
The Seattle → London route covers about 7,702 km and commonly 8–12 h nonstop or with 1 stop. Multiple carriers operate it — search FlyTiming to compare every airline and agency serving SEA → LHR in one search.
What is the cheapest day to fly from Seattle to London?
It varies by month. The price card on this page highlights the cheapest month and the historically cheapest day of the week to fly this route — the Low Fare Calendar below marks low-fare days in green.
When is the best time to book flights from Seattle to London?
As a rule of thumb, fares on international routes are usually lowest roughly 3–12 weeks before departure — and northern-summer peak (June–August) usually means the highest fares — book early or aim for the shoulder months. The calendar below is the fastest way to spot the cheapest months for Seattle → London.