Find flights
Deals
When to book
Airlines
FAQs

Cheap flights from Seattle to London from C$ 404

SEA — LON
20 Sep — 27 Sep1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in January or February, booked 82 days in advance, depart on a Saturday or Sunday and return on a Tuesday

Cheap flight deals from Seattle to London

Enter your travel dates to find the best prices.

Cheapest flights from Seattle to London

Tue 29/93:55 p.m. -
2 stops33h 00m
Fri 2/106:40 a.m. -
1 stop15h 05m
Deal found 20/8C$ 910
Fri 9/103:55 p.m. -
2 stops41h 05m
Mon 12/105:00 p.m. -
2 stops36h 58m
Deal found 21/8C$ 918
Sun 27/93:55 p.m. -
2 stops16h 30m
Sat 3/106:40 a.m. -
1 stop15h 05m
Deal found 20/8C$ 969
Sun 27/93:55 p.m. -
2 stops20h 00m
Sat 10/105:30 p.m. -
2 stops28h 15m
Deal found 17/8C$ 982
Tue 22/93:55 p.m. -
1 stop16h 05m
Thu 1/107:30 p.m. -
1 stop26h 15m
Deal found 19/8C$ 983
Sun 4/103:55 p.m. -
2 stops20h 00m
Sun 11/106:40 a.m. -
2 stops15h 05m
Deal found 19/8C$ 984
Fri 2/107:15 a.m. -
2 stops22h 20m
Sun 4/106:40 a.m. -
2 stops15h 05m
Deal found 20/8C$ 987
Sat 26/93:55 p.m. -
2 stops18h 55m
Thu 8/106:40 p.m. -
1 stop27h 05m
Deal found 20/8C$ 991
Tue 6/103:55 p.m. -
1 stop18h 35m
Sun 11/106:40 a.m. -
2 stops15h 05m
Deal found 21/8C$ 995
Sat 19/93:55 p.m. -
2 stops38h 40m
Tue 22/96:40 a.m. -
1 stop15h 05m
Deal found 20/8C$ 1,004
Sat 26/93:55 p.m. -
1 stop17h 45m
Thu 1/107:30 p.m. -
1 stop26h 15m
Deal found 19/8C$ 1,005
Sat 17/103:40 p.m. -
1 stop14h 55m
Wed 28/1011:55 a.m. -
1 stop13h 05m
Deal found 20/8C$ 1,085

Find flight deals from Seattle to London

Round-trip from

C$ 910

One-way from

C$ 404

Popular in

June

Cheapest in

January

Average price

C$ 1,194

Good round-trip deal

C$ 1,345 or less

Good one-way deal

C$ 744 or less
Scandinavian Airlines
  • Scandinavian Airlines
  • 29/9-2/10
  • 3 total stops
  • 48h 05m total
  • Seattle to London
Search Deals
19/9
  • 19/9
  • 2 total stops
  • 16h 13m total
  • Seattle to London
Search Deals
Highest demand for flights based on searches. 20% potential increase in price (C$ 404 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease (C$ 61 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in August 2026
Search Deals
Price to beat on a round-trip flight from Seattle/Tacoma Intl to London (LON).
Search Deals
Price to beat on a one-way flight from Seattle/Tacoma Intl to London (LON).
Search Deals

Cheapflights Fare Finder

 
Use the filters below to find and compare flights from Seattle to London that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Sun 27/9

3:55 p.m.-7:55 p.m.

2 stops20h 00m

London Heathrow

Mon 12/10

6:40 a.m.-10:49 p.m.

2 stops24h 09m

C$ 1,074

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Sat 17/10

7:00 p.m.-2:35 p.m.

1 stop11h 35m

London Gatwick

Fri 30/10

11:55 a.m.-6:00 p.m.

1 stop13h 05m

C$ 1,091

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Sun 18/10

3:40 p.m.-2:40 p.m.

1 stop15h 00m

London Gatwick

Thu 29/10

11:55 a.m.-6:00 p.m.

1 stop13h 05m

C$ 1,091

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Tue 15/9

3:55 p.m.-6:50 p.m.

2 stops18h 55m

London Heathrow

Tue 22/9

7:05 a.m.-11:20 p.m.

2 stops24h 15m

C$ 1,108

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Tue 20/10

7:00 p.m.-11:55 a.m.

1 stop32h 55m

London Heathrow

Mon 26/10

8:35 p.m.-6:00 p.m.

1 stop28h 25m

C$ 1,183

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Fri 23/10

10:39 a.m.-1:35 p.m.

2 stops18h 56m

London Heathrow

Tue 27/10

10:20 a.m.-8:04 p.m.

2 stops40h 44m

C$ 1,184

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Wed 21/10

10:39 a.m.-4:00 p.m.

2 stops21h 21m

London Heathrow

Fri 30/10

6:40 a.m.-8:04 p.m.

2 stops20h 24m

C$ 1,184

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Mon 19/10

7:00 p.m.-2:40 p.m.

1 stop11h 40m

London Gatwick

Tue 27/10

11:55 a.m.-6:00 p.m.

1 stop13h 05m

C$ 1,198

SeattleLondon

SEA Seattle/Tacoma Intl - LHR London Heathrow

SEALHR

Seattle/Tacoma Intl

Sat 17/10

10:39 a.m.-6:30 p.m.

2 stops23h 51m

London Heathrow

Fri 30/10

6:40 a.m.-8:04 p.m.

2 stops20h 24m

C$ 1,226

SeattleLondon

SEA Seattle/Tacoma Intl - LGW London Gatwick

SEALGW

Seattle/Tacoma Intl

Tue 15/9

6:05 p.m.-6:50 p.m.

1 stop16h 45m

London Gatwick

Tue 22/9

10:20 a.m.-3:40 p.m.

1 stop13h 20m

C$ 1,234

Flights are sorted by cheapest round-trip flights first.

Deals found on 16/8

Showing 1-10 of 45 resultsSorted by cheapest first
1
2
3
...
5

Best time to book a flight from Seattle to London

Have a flexible travel schedule? Discover the best time to fly to London from Seattle with our price prediction graph.
Estimated round-trip price

Cheapflights Insights

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

What is the cheapest month to book a flight from Seattle to London?

Currently, January is the cheapest month in which you can book a flight from Seattle to London (average of C$ 888). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,670). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from SEA to LON?

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to London as you normally would.

Weekly flight availability from Seattle to London

The most flights from SEA to LON are scheduled on a Wednesday (25 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (19 on average).

How much does it cost to fly round-trip from Seattle to London?

Airfare is below average for this route at the moment.
Seattle to London flights typically cost between C$ 960 and C$ 1,364 in September.
The cheapest round-trip price found within the last 5 days was C$ 910 on Scandinavian Airlines (29 Sep-2 Oct).

What’s the top layover airport for flights from Seattle to London?

Reykjavik (KEF) – chosen by Cheapflights users on 81% of one-stop itineraries from Seattle to London on Cheapflights.

What’s the cheapest layover airport for flights from Seattle to London?

Dublin (DUB) is the most affordable 1-stop option, with an average round-trip price of C$ 741.

What’s the fastest layover option from Seattle to London?

Flights via Dublin (DUB) have the shortest average one-way travel time for 1-stop routes: 11h 30m.

Which airport typically offers the quickest layover for flights from Seattle to London?

Flights via Salt Lake City (SLC) offer the fastest connection on this route, with an average layover time of 1h 53m.

How often are flights from Seattle to London delayed?

About 14% of weekly flights between Seattle and London have experienced delays in the past year, with the average delay time being 134 minutes.

What is the most punctual flight time for Seattle to London flights?

Historically, flights departing in the early afternoon are less likely to be delayed, whereas flights leaving in the evening tend to experience delays more often.

What day of the week experiences the fewest flight delays on this route?

Saturday tends to have the lowest number of delays on this route, whereas Wednesday has historically faced a higher average of delays compared to other days of the week.

Which airline has the best punctuality record on Seattle to London flights?

Over the past year, Virgin Atlantic has had the lowest number of delays on this route, with just 6% of flights being delayed.

How far ahead should I book a flight from Seattle to London?

The price you pay for your flight from Seattle to London may vary depending on when you book. For the best chance of a lower fare, look to book 64 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

Reviews of airlines servicing London

Get a feel of what it's like to fly with Virgin Atlantic from Seattle to London by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Virgin Atlantic
7.4
Good
695 reviews
Check prices

Crew

8.1

Overall

7.4

Food

6.9

Boarding

7.7

Comfort

7.3

Entertainment

7.5

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!
Virgin Atlantic
7.4
Good
695 reviews
Virgin Atlantic
7.4
Good
695 reviews
Check prices

Crew

8.1

Overall

7.4

Food

6.9

Boarding

7.7

Comfort

7.3

Entertainment

7.5

Reviews

1 / 20
6.0
Good

Pratap,Aug 2025

JFK - LHR

The flight is clean, food good and the staff are excellent! Very professional, polite and accommodating. The seat itself is really mediocre. Can’t believe there is not inch of storage space. Believe it or not it there is not place even to put away your phone or pen!! Very very surprising and terribly inconvenient. No coat hanger hook either. Had to give it away. ALL IN ALL VERY INCONVENIENT business class seat compared to their peers. What is even more surprising is that this on their relatively new fleet of Airbus A350-1000. I was having com platelets different expectations of Virgin and this has disappointed me. Everything else is just as good and as you would expect from Virgin!

Related info for your journey

  • What airport do you fly from for flights from Seattle to London?

    Most people fly from Seattle/Tacoma Intl (SEA) if they book a flight from Seattle to London. On average, Seattle/Tacoma Intl has 21 outbound flights to London per day from 1 airline. Seattle/Tacoma Intl is conveniently located just 18.4 km from Seattle’s city centre.

  • How long is the flight from Seattle to London?

    Icelandair, Scandinavian Airlines, and Condor can get you from Seattle to London in just under 11h 35m. Your travel time can differ by up to 5h 10m. The distance between Seattle and London is about 7736 km. This flight may include one or multiple stops.

  • What is the cheapest airline to fly from Seattle to London round-trip?

    According to our current data, Icelandair (C$ 695), offers the cheapest pricing from Seattle to London. This flight start at 39% lower than the current average price 3 months from now.

  • What are the most reliable airlines from Seattle to London?

    The top 3 most reliable airlines when flying from Seattle to London are SAUDIA (97%), Scandinavian Airlines (90%) and KLM (88%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 476. While the most popular route (Seattle/Tacoma Intl - London Gatwick) can be booked for C$ 1,737 on average, our data indicates C$ 1,145 when flying from Seattle to London.

  • Can I find deals for flights from Seattle to London that include hotel bookings?

    Yes. In addition to deals on Seattle to London flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to London?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to London.

  • Can I find deals for business class flights from Seattle to London?

    Yes. Cheapflights offers flight deals from Seattle to London by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to London?

    Currently, January is the cheapest month in which you can book a flight from Seattle to London (average of C$ 888). Flying from Seattle to London in June is currently the most expensive (average of C$ 1,670). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near London?

Book flights to London if you plan to visit one of these locations
Gatwick
Romford
Twickenham
Ilford
Bromley
Sutton
Luton
Slough
Marlow
Cobham
Hounslow
Watford
High Wycombe

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for Seattle to London

Seattle to Gatwick flights
Seattle to Heathrow flights
Seattle to Manchester flights

Top airline flying from Seattle to London

AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 695AverageC$ 865FlexibilityNo cancel feeOn-time76%
Search Icelandair flights

Fly with Cheapflights

How does Cheapflights help users find flights from Seattle to London?

Cheapflights helps you search for flights from Seattle to London via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

Why should you use Cheapflights to find cheap flight tickets from Seattle to London?

Cheapflights taps into our reliable network of hundreds of airlines and travel agencies to find the best deals for flights from Seattle to London for you. Better yet — we are completely free to use.

Can Cheapflights find flights from Seattle to London with no change fees?

Users can book flights with no change fees policies with our dedicated filters. Book flights from Seattle to London flexibly with Cheapflights today.

Can Cheapflights notify me if prices for flights from Seattle to London become cheaper?

Yes! Start tracking prices for Seattle to London flights today and get alerted whenever prices for these flights change. To access this feature, click the bell icon next to the flight deals above, which will prompt you for a valid email address to receive your alerts.

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.