Find cheap flights from Seattle/Tacoma Airport to London Heathrow Airport

SEA - LHR

Find cheap flights from Seattle/Tacoma Airport to London Heathrow Airport

Round-trip
Economy
Seattle (SEA)
London Heathrow
Mon. 13/7
Mon. 20/7
Any month
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Good to know

Low season

October Best time to beat the crowds (19% less expensive on average)

High season

June Most popular time to fly (34% more expensive on average)

Average price of a round-trip

C$ 662 (avg. price over the last 2 weeks)

Good deal for a round-trip

C$ 597 or less

When to book flights from Seattle/Tacoma Intl to London Heathrow

Estimated round-trip price
Average price per month
Flight prices as travel date approaches
-1 day
-2 days

Top tips for finding a cheap flight

  • Looking for a cheap flight? 25% of our users found flights on this route for C$ 661 or less.
  • The cheapest flight from Seattle/Tacoma Airport to London Heathrow Airport was found, on average, 89 days before departure.
  • Book at least 3 weeks before departure in order to get a below-average price.
  • High season is considered to be May, June and July. The cheapest month to fly is October.
*Average of the lowest prices shown in KAYAK’s search results for departures within the next 30 days

FAQs for booking Seattle/Tacoma Airport to London Heathrow Airport flights

How long does a flight from Seattle/Tacoma Airport to London Heathrow Airport take?

How many flights are there between Seattle/Tacoma Airport and London Heathrow Airport?

Which airlines provide the cheapest flights from Seattle/Tacoma Airport to London Heathrow Airport?

Which airlines fly most frequently between Seattle/Tacoma Airport and London Heathrow Airport?

What’s the cheapest day of the week to fly from Seattle/Tacoma Airport to London Heathrow Airport?

How does KAYAK’s flight Price Forecast tool help me choose the right time to buy?

Top 5 airlines serving Seattle/Tacoma Intl to London Heathrow

Scores according to KAYAK customer reviews

7.7
Finnair
Overall score based on 3,615 reviews
8.0
Boarding
7.6
Comfort
8.3
Crew
7.3
Entertainment
7.2
Food
Airline reviews
Read more about Finnair

Book cheap flights from Seattle/Tacoma Airport to London Heathrow Airport (round-trip)

Airports
Origin
Seattle
C$ 583
only
C$ 583
Destination
London
C$ 583
only
C$ 583
Tue., 15 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
Tue., 29 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 583
Trip: 15 days
Based on null reviews
Mon., 14 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Fri., 18 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
13h 00m
C$ 584
Trip: 5 days
Based on null reviews
Tue., 15 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Tue., 22 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 586
Trip: 8 days
Based on null reviews
Wed., 16 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Mon., 21 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
28h 30m
C$ 587
Trip: 6 days
Based on null reviews
Tue., 8 Dec.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
12h 20m
Tue., 15 Dec.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 45m
C$ 594
Trip: 8 days
Based on null reviews
Tue., 15 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Mon., 5 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
28h 30m
C$ 599
Trip: 21 days
Based on null reviews
Tue., 15 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Thu., 15 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 603
Trip: 31 days
Based on null reviews
Tue., 15 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
Tue., 22 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 606
Trip: 8 days
Based on null reviews
Sun., 1 Nov.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
12h 20m
Tue., 24 Nov.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 45m
C$ 609
Trip: 24 days
Based on null reviews
Mon., 14 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Mon., 21 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
28h 30m
C$ 610
Trip: 8 days
Based on null reviews
Tue., 22 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
Tue., 6 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 612
Trip: 15 days
Based on null reviews
Tue., 6 Oct.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
Mon., 12 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
28h 30m
C$ 613
Trip: 7 days
Based on null reviews
Tue., 6 Oct.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Mon., 12 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
28h 30m
C$ 614
Trip: 7 days
Based on null reviews
Wed., 14 Oct.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Wed., 21 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 617
Trip: 8 days
Based on null reviews
Tue., 22 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Tue., 6 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 620
Trip: 15 days
Based on null reviews
Sun., 13 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Tue., 29 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 621
Trip: 17 days
Based on null reviews
Tue., 13 Oct.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
Tue., 20 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 622
Trip: 8 days
Based on null reviews
Mon., 14 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
Wed., 30 Sep.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
28h 30m
C$ 624
Trip: 17 days
Based on null reviews
Wed., 16 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
20h 30m
Thu., 1 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 625
Trip: 16 days
Based on null reviews
Tue., 13 Oct.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
Tue., 20 Oct.
LHR
London Heathrow Airport
SEA
Seattle/Tacoma Airport
12h 50m
C$ 626
Trip: 8 days
Based on null reviews
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Book cheap flights from Seattle/Tacoma Airport to London Heathrow Airport (one-way)

Airports
Origin
Seattle
C$ 313
only
C$ 313
Destination
London
C$ 313
only
C$ 313
Tue., 8 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
55h 20m
C$ 313
Based on null reviews
Thu., 27 Aug.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
14h 05m
C$ 345
Based on null reviews
Mon., 24 Aug.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
C$ 387
Based on null reviews
Sun., 13 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
19h 08m
C$ 421
Based on null reviews
Mon., 20 Jul.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
9h 20m
C$ 557
Based on null reviews
Mon., 20 Jul.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
9h 20m
C$ 568
Based on null reviews
Mon., 14 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
53h 20m
C$ 322
Based on null reviews
Sun., 13 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
35h 53m
C$ 334
Based on null reviews
Thu., 27 Aug.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
C$ 389
Based on null reviews
Wed., 2 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
43h 50m
C$ 370
Based on null reviews
Mon., 14 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
C$ 414
Based on null reviews
Thu., 3 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
26h 33m
C$ 476
Based on null reviews
Wed., 9 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
47h 38m
C$ 376
Based on null reviews
Sun., 12 Jul.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
C$ 450
Based on null reviews
Mon., 20 Jul.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
14h 00m
C$ 571
Based on null reviews
Wed., 19 Aug.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
9h 20m
C$ 587
Based on null reviews
Mon., 7 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
11h 55m
C$ 451
Based on null reviews
Thu., 3 Sep.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
36h 35m
C$ 424
Based on null reviews
Mon., 20 Jul.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
33h 00m
C$ 575
Based on null reviews
Tue., 11 Aug.
SEA
Seattle/Tacoma Airport
LHR
London Heathrow Airport
9h 20m
C$ 614
Based on null reviews
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*
Prices are per person, are for e–tickets and include all taxes & fees in CAD.

We attempt to get accurate prices, however, prices are not guaranteed.

Here's why:

We’re not the seller.
At KAYAK we don’t set the prices, so it’s not possible for us to guarantee what other companies are selling.

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Our service lets you quickly and easily compare results from hundreds of travel sites at once. In this sense, KAYAK is a search engine and we can't guarantee prices we find.

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Prices on airline seats, hotel rooms and car rentals can change frequently. Several people may also be trying to buy the same travel option simultaneously. As a result, you may find, on occasion, that certain prices are no longer available.

If you have more questions or if you have a bad price to report to us,
please send us an and someone from our team will get back to you promptly.

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The fares displayed include all taxes and fees for economy class travel and were found by the provider in the last 72 hours. Seats are limited and may not be available on all flights and days. Fares are subject to change and may not be available on all flights or dates of travel. Some carriers charge additional fees for extra checked bags. Please check the carriers' sites.
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