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C$279 Cheap Flights from Seattle / Tacoma International (SEA) to London Heathrow (LHR)

Compare Seattle / Tacoma International to London Heathrow flight deals

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Flight deals from Seattle / Tacoma International to London Heathrow

Looking for a cheap last-minute deal or the best return flight from Seattle / Tacoma International Airport to London Heathrow Airport? If you want to travel next month, return fares start from C$999. Find the lowest prices on one-way and return tickets right here.
London.C$279 per passenger.Departing Tue., Feb. 2.One-way flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Seattle / Tacoma International on Tue., Feb. 2, arriving in London Heathrow.Price includes taxes and charges.From C$279, select.
London.C$279 per passenger.Departing Tue., Jan. 26.One-way flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Seattle / Tacoma International on Tue., Jan. 26, arriving in London Heathrow.Price includes taxes and charges.From C$279, select.
London.C$281 per passenger.Departing Tue., Apr. 20.One-way flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Seattle / Tacoma International on Tue., Apr. 20, arriving in London Heathrow.Price includes taxes and charges.From C$281, select.
London.C$356 per passenger.Departing Fri., Dec. 4.One-way flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Seattle / Tacoma International on Fri., Dec. 4, arriving in London Heathrow.Price includes taxes and charges.From C$356, select.
London.C$366 per passenger.Departing Sun., Jul. 12.One-way flight with Icelandair.Outbound indirect flight with Icelandair, departs from Seattle / Tacoma International on Sun., Jul. 12, arriving in London Heathrow.Price includes taxes and charges.From C$366, select.
London.C$370 per passenger.Departing Sun., Aug. 30.One-way flight with Icelandair.Outbound indirect flight with Icelandair, departs from Seattle / Tacoma International on Sun., Aug. 30, arriving in London Heathrow.Price includes taxes and charges.From C$370, select.
London.C$374 per passenger.Departing Mon., Nov. 2.One-way flight with Icelandair.Outbound indirect flight with Icelandair, departs from Seattle / Tacoma International on Mon., Nov. 2, arriving in London Heathrow.Price includes taxes and charges.From C$374, select.
London.C$383 per passenger.Departing Fri., Oct. 9.One-way flight with Icelandair.Outbound indirect flight with Icelandair, departs from Seattle / Tacoma International on Fri., Oct. 9, arriving in London Heathrow.Price includes taxes and charges.From C$383, select.
London.C$399 per passenger.Departing Wed., Sep. 30.One-way flight with Icelandair.Outbound indirect flight with Icelandair, departs from Seattle / Tacoma International on Wed., Sep. 30, arriving in London Heathrow.Price includes taxes and charges.From C$399, select.
London.C$430 per passenger.Departing Sat., Mar. 20.One-way flight with Alaska Airlines.Outbound indirect flight with Alaska Airlines, departs from Seattle / Tacoma International on Sat., Mar. 20, arriving in London Heathrow.Price includes taxes and charges.From C$430, select.
London.C$439 per passenger.Departing Mon., Jun. 29.One-way flight with Icelandair.Outbound indirect flight with Icelandair, departs from Seattle / Tacoma International on Mon., Jun. 29, arriving in London Heathrow.Price includes taxes and charges.From C$439, select.
London.C$443 per passenger.Departing Mon., Sep. 14.One-way flight with Alaska Airlines.Outbound direct flight with Alaska Airlines departs from Seattle / Tacoma International on Mon., Sep. 14, arriving in London Heathrow.Price includes taxes and charges.From C$443, select.
London.C$447 per passenger.Departing Mon., Oct. 12.One-way flight with American Airlines.Outbound direct flight with American Airlines departs from Seattle / Tacoma International on Mon., Oct. 12, arriving in London Heathrow.Price includes taxes and charges.From C$447, select.
London.C$447 per passenger.Departing Tue., Feb. 2.One-way flight with Delta.Outbound direct flight with Delta departs from Seattle / Tacoma International on Tue., Feb. 2, arriving in London Heathrow.Price includes taxes and charges.From C$447, select.
London.C$447 per passenger.Departing Mon., Nov. 2.One-way flight with British Airways.Outbound direct flight with British Airways departs from Seattle / Tacoma International on Mon., Nov. 2, arriving in London Heathrow.Price includes taxes and charges.From C$447, select.
London.C$447 per passenger.Departing Sun., Mar. 14.One-way flight with Iberia.Outbound direct flight with Iberia departs from Seattle / Tacoma International on Sun., Mar. 14, arriving in London Heathrow.Price includes taxes and charges.From C$447, select.

Find the cheapest month to fly from Seattle / Tacoma International to London Heathrow

We’re always keeping an eye on fares, so you can find the best one in seconds. It looks like Seattle / Tacoma International to London Heathrow flights are currently cheapest in January.
Jun.
from C$439
Jul.
from C$366
Aug.
from C$370
Sep.
from C$399
Oct.
from C$383
Nov.
from C$374
Dec.
from C$356
Jan.
from C$279
Feb.
from C$279
Mar.
from C$430
Apr.
from C$281
May
from C$448

Which airlines fly from Seattle / Tacoma International to London Heathrow?

Seattle / Tacoma International to London Heathrow: Alternative routes

Compare routes from Seattle / Tacoma International to London below. You may find an airport to fly into that's cheaper, faster, or easier than London Heathrow.

London City

12km from central London
Closest
from C$454
Search flights

London Heathrow

23km from central London
Cheapest
from C$279
Search flights

London Gatwick

40km from central London
from C$367
Search flights

London Luton

45km from central London
from C$361
Search flights

London Stansted

49km from central London
from C$327
Search flights

London Southend

57km from central London
from C$468
Search flights

Seattle to London: Flight information

The things to know before you go.
Cheapest flight foundC$279
Cheapest month to flyJanuary
Average flight time9 hrs, 36 mins
Most popular airlineAlaska Airlines
Average flights per week155

Finding cheap flights from Seattle / Tacoma International to London Heathrow: Frequently asked questions

The best price we found for a return flight from Seattle / Tacoma International to London Heathrow is C$807. This is an estimate based on information collected from different airlines and travel providers over the last 4 days and is subject to change and availability.
9 hours and 36 minutes is the average flight time from Seattle / Tacoma International to London Heathrow.
Alaska Airlines, Air France and Delta fly direct from Seattle / Tacoma International to London Heathrow.
As of June 2026, there are 155 flights per week flying from Seattle / Tacoma International to London Heathrow.
The cheapest month to fly from Seattle / Tacoma International to London Heathrow is usually August.
After crunching the numbers on our flight calendar, we found that it's currently cheapest to fly from Seattle / Tacoma International Airport to London Heathrow Airport on Thursday, August 20, 2026.
Yes – the average flight time is 9 hours and 36 minutes.
We show every price from over 1,200 airlines and travel agents, comparing them all so you don’t have to. If you know you want to fly to London Heathrow but you’re not ready to book, set up a Price Alert. We’ll track prices for you, and let you know when they rise or fall.
We crunched all the numbers in our flight calendar and it looks like the cheapest time to book a flight to London is around 40 days in advance, so don’t leave your flight to the last minute.
Currently, Air Canada and Alaska Airlines offer the cheapest flight tickets to London Heathrow.

Flying from Seattle-Tacoma International Airport (SEA) to London Heathrow Airport (LHR): what you need to know

  • The average duration of a direct flight from Seattle-Tacoma International Airport to London Heathrow Airport is 9 hours 26 minutes. London's timezone is UTC+0, making London 7 hours ahead of Seattle.

  • Flights from Seattle-Tacoma International Airport to London Heathrow Airport start from 09:25 — the first with British Airways. The last flight of the day is the 21:20 service with Delta Air Lines. In total, you can take your pick of 37 services every week between SEA and LHR.

  • Traveling during a peak time like July? School holidays and other high seasons can lead to longer queues and delays at check-in and security. Be extra cautious and get there up to four hours before international flights and two hours before domestic departures.

  • One easy trip from SEA to LHR is all it takes to get to London, United Kingdom. You'll have a variety of carriers that run direct flights from Seattle-Tacoma International Airport to London Heathrow Airport, including:

  • To break up your flight from Seattle-Tacoma International Airport to London Heathrow Airport, add a stopover to your trip. Simply deselect 'Direct flights only' to find a city that interests you. The most popular stopovers on the SEA - LHR route include:

    • Vancouver International Airport

    • Keflavik International Airport

    • Charles de Gaulle Airport

How to find the cheapest flights from Seattle-Tacoma International Airport (SEA) to London Heathrow Airport (LHR)

  • C$279 is currently the lowest price for a one-way ticket from Seattle-Tacoma International Airport to London Heathrow Airport. Return flights start at C$807. These fares can change based on demand and availability.

  • To get your hands on cheap flight tickets from SEA to LHR, reserve your journey 3 months ahead of the departure date.

  • The cheapest month for flight tickets from Seattle-Tacoma International Airport to London Heathrow Airport is November. Use the 'Whole month' tool to find the lowest prices if you have flexible travel dates.

  • Getting a cheap ticket from SEA to LHR is a piece of cake with Price Alerts. All you need to do is create one of these automatic alerts and we'll get in touch when there's a better deal.

  • Tailor your trip with filters. Pick your preferred departure and arrival times, airlines and total journey duration. You can also sort results by 'Best,' 'Cheapest' or 'Fastest' flights from Seattle-Tacoma International Airport to London Heathrow Airport.

Handy information about Seattle-Tacoma International Airport (SEA)

  • Traveling from central Seattle to Seattle-Tacoma International Airport takes around 54 minutes on public transport. If you drive, ride-share or grab a cab, you'll cover the 23 kilometres in 18 minutes or so, depending on traffic.

  • Have an early flight from Seattle-Tacoma International Airport to London Heathrow Airport? Avoid the last-minute rush to the airport (and enjoy a little extra shut-eye) by choosing one of these hotels near SEA:

Arriving at London Heathrow Airport (LHR)

Getting from London Heathrow Airport (LHR) to central London

  • From London Heathrow Airport, London is approximately 31 kilometres away. It takes around 57 minutes to get to the center driving.

  • It takes around 1 hour and 1 minute if you're using public transport.

When to fly to London Heathrow Airport (LHR)

  • The quietest month for a flight from Seattle-Tacoma International Airport to London Heathrow Airport is February, while July is the most popular. Pick the best time to go to London based on whether you prefer a bustling atmosphere or a more laid-back vibe.

  • The warmest month in London is July, with the temperature ranging between 11ºC and 26ºC. Lock in your flights from Seattle-Tacoma International Airport to London Heathrow Airport in this month if you enjoy this type of weather.

  • January sees average temperatures of between 0ºC and 9ºC. Search for cheap flight tickets from SEA to LHR sometime then if you like traveling in cooler conditions.

More about London

Complete your London trip with hotels and a car rental

  • You've locked in your cheap ticket to London Heathrow Airport — now it's time to find a great place to stay, and maybe even your own set of wheels. We've compared prices across hundreds of companies to bring you the best hotels and car rental deals in London.

More travel options

Plan the rest of your trip from Seattle to London

Prices shown on this page are estimated lowest prices only. Found in the last 45 days.