Cheapest Day to Buy Flights from London to Seattle
Low Fare Calendar — London to Seattle
When to book vs. when to fly — London → Seattle
Live data from recent Aviasales searches for LHR → SEA, 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 — London → Seattle
Flight options — London → Seattle
Recently-seen round-trip fares — click any flight for details, alternatives and booking.
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FAQ — LHR → SEA
How much is a flight from London to Seattle?
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 London (LHR) and Seattle (SEA).
Which airlines fly from London to Seattle?
The London → Seattle 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 LHR → SEA in one search.
What is the cheapest day to fly from London to Seattle?
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 London to Seattle?
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 London → Seattle.