$551 Cheap Flights from London (LON) to Seattle (SEA)

Popular airlines from London to Seattle, WA (SEA-Seattle - Tacoma Intl.)

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Find available prices by choosing your travel dates.

Cheap Flights from London to Seattle (LON-SEA)

Prices were available within the past 7 days and start at $551 for one-way flights and $529 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Icelandair
Lufthansa
Swiss International Air Lines
Lufthansa
United
British Airways
Delta
American Airlines
Iberia
Air Canada
Flights from London (LGW) to Seattle (SEA)
Origin airport
Gatwick
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Aer Lingus, Air Canada, Air France, American Airlines, Austrian Airlines, British Airways, Brussels Airlines, Delta, Finnair, Iberia, Icelandair, JetBlue Airways, KLM, Lufthansa, Scandinavian Airlines, Swiss International Air Lines, Turkish Airlines, United, Virgin Atlantic, WestJet
Roundtrip price
$529
Distance
4810 mi

London to Seattle Flights

The cheapest times to fly from London to Seattle

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from London to Seattle are during the month of October. You can find some of the cheapest flights from London to Seattle with Expedia's search tool and vast selection of airlines.

The best time to book a flight from London to Seattle

Sunday is one of the best days to book for cheap flights from London to Seattle: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

How to find cheap round-trip tickets from London to Seattle

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from London to Seattle in 2025. You can also book with separate airlines for your outbound and return journeys, from $551 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap London to Seattle flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

You could also save big by booking one of Expedia's vacation packages. Bundling together your London to Seattle airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

*Terms apply.

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

Frequently asked questions

How much is a flight from London (LON-All Airports) to Sea-Tac Airport?
Within the past 7 days on Expedia, for flights departing within the next year, the lowest price advertised for a round-trip journey from London (LON-All Airports) to Sea-Tac Airport was $529. Cheap tickets don’t wait forever, so book yours today. Prices and availability are subject to change. Additional terms apply.
Do I need to pay a cancellation fee if I cancel my flight from London (LON-All Airports) to Seattle - Tacoma Intl. Airport (SEA)?
This can vary between airlines, as each has its own terms and conditions. Visit the Customer Service Portal, where you’ll find easy-to-follow instructions on how to cancel your flight online.
How do I find cheap flights from London (LON-All Airports) to Sea-Tac Airport that have flexible change policies?
Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you’re searching for London (LON-All Airports) to SEA flights, you’ll see a “no change fees” filter for you to select.
How far is the flight from London (LON-All Airports) to Sea-Tac Airport?
The distance is around 4786 mi, so fill your carry-on bag with all you need to make your journey comfortable. Not sure what to take on board your England to SeaTac flight? A travel pillow, earplugs and a sleep mask are a few essentials.
Which airlines fly direct from London (LON-All Airports) to SEA?
Whether you’re after a one-way or return flight, you’ll have your choice of airlines that will take you straight from London (LON-All Airports) to Sea-Tac Airport. These are some of the most popular ones:

  • Virgin Atlantic - (VS) with 30 monthly flights
  • American Airlines - (AA) with 30 monthly flights
  • British Airways - (BA) with 30 monthly flights
  • Delta Air Lines - (DL) with 17 monthly flights

Are London (LON-All Airports) to SEA flight tickets cheaper when they're purchased at the last minute?
Flight prices go up and down like a yo-yo, so not always. While last-minute deals between London (LON-All Airports) and Sea-Tac Airport are of course possible, it’s also a good idea to keep a close eye on prices well before you fly. In fact, some carriers publish their prices up to a year before the departure date. Expedia is continuously updating the biggest bargains around, so keep checking back and be ready to book when the price is right.

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*Available to One Key members.