SEA - LHR

C$ 519 Find Cheap Flights from Seattle to London Heathrow Airport

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Seattle to London departing on 29/4. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to London Heathrow Airport

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to London, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to London, as well as popular online travel agencies
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Everything you should know

Cheapest round-trip
C$ 754
Overall average: C$ 921
Icelandair
Mon 2/3Fri 13/3
SEA - LHR • 1 stop
Cheapest direct flights
C$ 878
Typical prices: C$ 838-C$ 1,114
British Airways
Tue 10/3Fri 20/3
SEA - LHR • Direct
Our travellers' advice
AI-powered summary based on content written by travel experts and KAYAK users. AI can make mistakes.
Virgin's Economy Delight offers extra legroom and priority.
Pack a lunch as airport food can be costly.
Expert advice
Expert advice
+1
+1
Expert advice
Expert advice
+1
Top airlines
Icelandair
Cheapest • from C$ 754 (round-trip)
Virgin Atlantic
Best reviews • 7.5 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to book
2 weeks
in advance
Our data shows that travellers who book at least 2 weeks in advance save around 16% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
January
Cheapest • 17% price drop
August
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
KAYAK searches hundreds of sites at once to find you the best travel deals.
We hope you love your trip to London!
Flight Deals
Booking Insights
Expert advice
Flight Deals

Cheap Flights from Seattle to London (SEA-LHR)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle to London that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to London

Mon, 2 Mar - Fri, 13 Mar
Icelandair Logo
2:35 p.m. - 10:50 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
12:15 p.m. - 6:00 p.m.
LHR
-
SEA
12h 45m
1 stop
C$ 754Icelandair
Tue, 3 Mar - Tue, 10 Mar
Icelandair Logo
2:35 p.m. - 10:50 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
12:15 p.m. - 6:00 p.m.
LHR
-
SEA
12h 45m
1 stop
C$ 755Icelandair
Sun, 8 Mar - Mon, 16 Mar
Icelandair Logo
3:35 p.m. - 10:50 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
8:35 p.m. - 6:00 p.m.
LHR
-
SEA
28h 25m
1 stop
C$ 757Icelandair
Thu, 5 Mar - Sun, 8 Mar
Icelandair Logo
2:35 p.m. - 10:50 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
8:35 p.m. - 6:00 p.m.
LHR
-
SEA
28h 25m
1 stop
C$ 773Icelandair
Sun, 12 Apr - Wed, 22 Apr
Icelandair Logo
7:00 p.m. - 8:20 p.m.
SEA
-
LHR
17h 20m
1 stop
Icelandair Logo
1:05 p.m. - 5:55 p.m.
LHR
-
SEA
12h 50m
1 stop
C$ 776Icelandair
Tue, 14 Apr - Tue, 28 Apr
Icelandair Logo
3:40 p.m. - 11:55 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
1:05 p.m. - 5:55 p.m.
LHR
-
SEA
12h 50m
1 stop
C$ 777Icelandair
Sat, 18 Apr - Mon, 27 Apr
Icelandair Logo
7:00 p.m. - 8:20 p.m.
SEA
-
LHR
17h 20m
1 stop
Icelandair Logo
9:25 p.m. - 5:55 p.m.
LHR
-
SEA
28h 30m
1 stop
C$ 779Icelandair
Mon, 9 Mar - Tue, 17 Mar
Icelandair Logo
3:35 p.m. - 10:50 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
12:15 p.m. - 6:00 p.m.
LHR
-
SEA
12h 45m
1 stop
C$ 780Icelandair
Tue, 24 Feb - Thu, 5 Mar
Icelandair Logo
2:35 p.m. - 10:50 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
12:15 p.m. - 5:00 p.m.
LHR
-
SEA
12h 45m
1 stop
C$ 781Icelandair
Sun, 26 Apr - Thu, 7 May
Icelandair Logo
3:40 p.m. - 11:55 a.m.
SEA
-
LHR
12h 15m
1 stop
Icelandair Logo
1:05 p.m. - 5:55 p.m.
LHR
-
SEA
12h 50m
1 stop
C$ 787Icelandair
Booking Insights

KAYAK's insights & trends for Seattle to London flights

Get data-powered insights and trends into flights from Seattle to London to help you find the cheapest flights, the best time to fly and much more.

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

The average price of all round-trip flights from Seattle to London Heathrow Airport clicked on KAYAK for each day over the last 12 months.

If your flying dates are flexible, you should consider flying to London Heathrow Airport on a Sunday, as we generally find the cheapest rates on that day for this route. On the other hand, Tuesday is the most expensive day to fly from Seattle to London Heathrow Airport. For your return ticket, we recommend flying on a Monday and avoiding Thursdays for the best deals.

What is the cheapest month to fly from Seattle to London Heathrow Airport?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Seattle to London Heathrow Airport, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Seattle to London Heathrow Airport is January, where tickets cost C$ 872 (return) on average. On the other hand, the most expensive months are June and December, where the average cost of round-trip tickets is C$ 1,444 and C$ 1,325 respectively.

Can I save money by flying with a layover from Seattle to London Heathrow Airport?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

No, with an average price for the route of C$ 768, prices are generally cheapest when you fly direct.

How far in advance should I book a flight from Seattle to London Heathrow Airport?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Seattle to London Heathrow Airport, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Seattle to London Heathrow Airport, you should book around 2 weeks before departure, which saves you about 16% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

Expert advice

Expert advice for your flight from Seattle to London

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Stefanie Waldek

Stefanie Waldek

Expert on Delta

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Laura Ratliff

Laura Ratliff

Expert on Virgin Atlantic

Laura Ratliff is a New York-based writer and editor. She lives in downtown Brooklyn with her husband and their beloved dogs. Originally from Texas, she now considers New York City her home. She typically spends more than 200,000 miles on a plane each year and stays in plenty of hotels.

Duncan Madden

Duncan Madden

Expert on British Airways and LHR

Duncan is a freelance travel writer, copywriter and book author in constant search of travel stories and the perpetual sensation of being on holiday. He’s never happier than when on a dusty trail in search of empty waves or ducking under the piste tape in search of snowbound solitude. British born, living in Germany, but happiest heading for the horizon. His first book, Found in Translation, explores the etymologies and stories of country names around the world and is out now.

Harriet Baskas

Harriet Baskas

Expert on SEA

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Good to know

Low seasonJanuary
Cheapest flightC$ 519
Best time to beat the crowds (18% less expensive on average)
Most popular time to fly and prices are also 9% lower on average.
Flight from Seattle to London Heathrow Airport

When to book flights from Seattle to London

Are your dates flexible? Find out the best times to travel from Seattle to London based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

Flights from Seattle to London: the best tips from KAYAK users' own experiences

Insights shared by verified travellers who flew the route from Seattle to London 
Verified travelerFlew with British Airways
SEA
-
LHR
Apr 2025
Make sure you have plenty of time between flights if you are delayed.
Verified travelerFlew with British Airways
SEA
-
LHR
Feb 2025
Don’t take a flight if you sick, or if you have no choice prepare to stay covered with mask throughout the flight
Verified travelerFlew with British Airways
SEA
-
LHR
Apr 2024
Bring a sack lunch -- airport food was very expensive.

FAQs for booking Seattle to London Heathrow Airport flights

  • What is the cheapest flight from Seattle to London Heathrow Airport?

    In the last 3 days, the lowest price for a flight from Seattle to London Heathrow Airport was C$ 519 for a one-way ticket and C$ 754 for a round-trip.

  • Which airlines offer Wi-Fi service onboard planes from Seattle to London Heathrow Airport?

    All the following airlines offer inflight Wi-Fi service on the Seattle to London Heathrow Airport flight route: Air France, Delta, Virgin Atlantic, KLM, Scandinavian Airlines, and American Airlines.

  • Which aircraft models fly most regularly from Seattle to London Heathrow Airport?

    The Boeing 787-10 Dreamliner is the aircraft model that flies most regularly on the Seattle to London Heathrow Airport flight route.

  • Which airline alliances offer flights from Seattle to London Heathrow Airport?

    oneworld, and SkyTeam are the airline alliances operating flights between Seattle and London Heathrow Airport, with oneworld being the most commonly used for this route.

  • On which days can I fly direct from Seattle to London Heathrow Airport?

    There are direct flights from Seattle to London Heathrow Airport on a daily basis.

  • Which is the best airline for flights from Seattle to London, Virgin Atlantic or Icelandair?

    The two airlines most popular with KAYAK users for flights from Seattle to London are Virgin Atlantic and Icelandair. With an average price for the route of C$ 936 and an overall rating of 7.5, Virgin Atlantic is the most popular choice. Icelandair is also a great choice for the route, with an average price of C$ 710 and an overall rating of 7.1.

  • How does KAYAK find such low prices on flights from Seattle to London Heathrow Airport?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Seattle to London Heathrow Airport.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Seattle to London Heathrow Airport?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London Heathrow Airport from Seattle is likely to change within 7 days, so travellers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Seattle to London Heathrow Airport?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to London Heathrow Airport with an airline and back to Seattle with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Seattle to London Heathrow Airport?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to London Heathrow Airport from Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Seattle to London Heathrow Airport

  • Looking for a cheap flight? 25% of our users found flights on this route for C$ 441 or less one-way and C$ 974 or less round-trip.

Prefer to fly direct from Seattle to London Heathrow Airport?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Seattle/Tacoma Intl to London Heathrow.
Find which airlines fly direct from Seattle/Tacoma Intl Airport to London Heathrow Airport, which days they fly and book direct flights.

Direct departures

Seattle/Tacoma Intl to London Heathrow

Monday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Tuesday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Wednesday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Thursday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Friday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Saturday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Sunday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

See more nonstop flights

Direct returns

London Heathrow to Seattle/Tacoma Intl

Monday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Tuesday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Wednesday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Thursday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Friday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Saturday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

Sunday

British Airways,Delta,Virgin Atlantic

British Airways,Delta, +1 more

See more nonstop flights

Reviews of the top 3 airlines flying from Seattle to London

 
See real verified KAYAK customer reviews for airlines flying from Seattle to London. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Seattle to London? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.5
Virgin AtlanticOverall score based on 678 reviews
7.3Comfort
7.6Entertainment
8.2Crew
7.7Boarding
6.9Food
Airline reviews

Food has been disappointing in both legs of flight to india

10.0 ExcellentRanj, Nov 2025
DEL - LHR
Read more Virgin Atlantic reviews

Food has been disappointing in both legs of flight to india

Great staff great experience, made a 2 hour delay very bearable

Great staff, great experience, made a 2 hour delay very bearable

Food was the worst I’ve had on a VA flight. Normally it’s a lot better

I was my pleasure to fly virgin on my birthday for my first solo trip ever 🫶🏼

These are one of the older seat arrangements facing away from the windows! Not particularly convenient sets. No storage spaces. NO COAT HANGING HOOKS. Inconvenient business class seat compared to any other airlines of similar class. Staff are excellent! Extremely professional, friendly. Food is good too.

Overall, flight was excellent but check in was very slow for Premium Economy. Economy queue was shorter but we weren't allowed to use it.

The staff was not very polite but the flight was very very nice and comfortable and the entertainment was great

Great crew - old style upper class seats on the older fleet now feels dated

Premium economy more comfortable than economy, but not by much. Did was awful, do not try the omelette. Flight crew were helpful. Flight was delayed by over an hour. Overall but bad, arrived safely and thank God.

The staff was kind and helpful. There was no food, and you needed to bring your own earphones to use the entertainment, which I didn’t know.

They wouldn’t check in my luggage even though I had one checked bag prepaid. So I took my bag to the gate and tried to check it in there and two employees scolded me for bringing a large bag to the gate. I told them I was trying to check it in and that it was prepaid, and they said they couldn’t guarantee that it would arrive at my destination but they finally let me drop it off when boarding the plane and pick it up right after exiting the plane. There was no food, and there was no entertainment.

The customer service was unbeatable from the wheelchair assist team to the flight attendants. The pilot also did an excellent job managing the turbulence.

Delays at check-in, seemed like they were short ground staff at the time and some passengers needed extra processing.

Problems checking in both on the laptop and on the app. No free seating available at check-in as advertised - must pay for EVERY seat between $23 and $75. No way to cancel seat choice. App menus and site menus are not responsive, and some items are impossible to find. Crew and mobile assistance are friendly and helpful.

Food - Non-Existent. You pay for everything. It is strictly Pay-to-Play!

Again, we paid $ 328.00 for specific seats are were assigned those seats.

Iceland air transfer was bad. They lost my luggage and I just received it 11/1

It was too cold in the plane my feet froze

Handling our luggage was the biggest issue - they lost it and we got it almost 3 days later. Really threw off the beginning of our trip and we really had to change our itinerary accordingly.

They had us seating down for one hour just waiting on the plane

Flying with BA is always a good experience—even in economy class. It is better if in business and first class. Timely, breeze through security and timely connections

We waited at BOS at the gate for an hour and couldn’t get a drink or anything. Once in the air the service, food and ride was excellent.

My enetertainmnet screen was broken. Lost my bags. Almost missed my flight do to connection issues with (despite a request) ZERO help from crew. Food was edible. Potatoes pretty good even

The issue was not with BA it was with the link yoiu sent fopr booking the flight

Loved the boarding option from Business class lounge, experience on flight was excellent, plenty of good food choices

The airline was not clear about a new departure time so we got to the airport early anyway. The flight left early which was great because of weather. The check in process was very easy and staff were friendly and helpful. The crew was great and our flight was very good.

Awful it always is unfortunately is the only way to fly direct to london

I travelled in business class and was disappointed by lack of service, curt and borderline rude time of the crew and to top it off, all of my luggage was delayed. It was like pulling teeth to even report the missing luggage and recover it the next day from the airport.

Boarding was poor. All groups called immediately one after the other resulting in a long queue in the jetty/jet bridge. Seats were very hard and and did not recline on a 4.5 hour flight. No food was available. Plane was cold. There was no entertainment.

Everything you need to know for your flight from Seattle to London

Information on your arrival and departure airports