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Cheap flights from Seattle to London from C$ 403

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 5/10. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
4 May — 11 May1
1 adult

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or January, booked 75 days in advance, depart on a Sunday or Tuesday and return on a Friday

Cheap flight deals from Seattle to London

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to London (LON). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 29 April 2025.

Round-trip from

C$ 864

One-way from

C$ 403

Popular in

June

Cheapest in

October

Average price

C$ 947

Good round-trip deal

C$ 1,013 or less

Good one-way deal

C$ 560 or less
Scandinavian Airlines
  • Scandinavian Airlines
  • 10/9-19/9
  • 2 total stops
  • 48h 40m total
  • Seattle to London
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Icelandair
  • Icelandair
  • 5/10
  • 1 total stop
  • 14h 55m total
  • Seattle to London
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Highest demand for flights based on searches. 18% potential increase in price (C$ 340 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease (C$ 53 potential savings vs. average RT price).
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Average for round-trip flights in April 2025
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to London (LON).
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Price to beat on a one-way flight from Seattle/Tacoma Intl to London (LON).
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Find flight deals from Seattle to London

Cheapest flights from Seattle to London
Explore the most affordable flight options available from Seattle to London. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 29 April 2025.

Wed 10/94:00 p.m.SEA - LHR
1 stop33h 20mScandinavian Airlines
Fri 19/96:40 a.m.LHR - SEA
1 stop15h 20mScandinavian Airlines
Deal found 28/4C$ 864
Fri 26/97:00 p.m.SEA - LGW
1 stop11h 40mIcelandair
Sat 4/103:40 p.m.LGW - SEA
1 stop13h 00mIcelandair
Deal found 28/4C$ 878
Tue 23/93:45 p.m.SEA - LHR
1 stop12h 10mIcelandair
Fri 3/101:05 p.m.LHR - SEA
1 stop12h 45mIcelandair
Deal found 28/4C$ 894
Wed 3/97:20 a.m.SEA - LHR
1 stop15h 10mUnited Airlines
Wed 17/96:30 a.m.LHR - SEA
2 stops20h 06mUnited Airlines
Deal found 28/4C$ 937
Wed 6/85:30 a.m.SEA - LGW
2 stops20h 30mVirgin Atlantic
Tue 19/812:00 p.m.LGW - SEA
1 stop18h 53mVirgin Atlantic
Deal found 28/4C$ 941
Wed 27/87:20 a.m.SEA - LHR
1 stop18h 40mMultiple Airlines
Mon 15/98:05 p.m.LHR - SEA
2 stops30h 31mMultiple Airlines
Deal found 28/4C$ 947
Tue 23/95:35 p.m.SEA - LHR
Nonstop9h 45mDelta
Thu 2/106:30 a.m.LHR - SEA
1 stop13h 20mDelta
Deal found 28/4C$ 954
Wed 13/810:00 a.m.SEA - LHR
2 stops17h 50mLufthansa
Thu 21/85:50 p.m.LHR - SEA
1 stop31h 09mLufthansa
Deal found 28/4C$ 966
Mon 25/84:25 p.m.SEA - LGW
1 stop17h 25mSWISS
Tue 9/96:35 p.m.LGW - SEA
2 stops32h 01mSWISS
Deal found 28/4C$ 969
Mon 1/94:25 p.m.SEA - LHR
1 stop17h 25mSWISS
Mon 8/98:05 p.m.LHR - SEA
2 stops30h 31mSWISS
Deal found 28/4C$ 974
Wed 30/711:34 a.m.SEA - LGW
1 stop14h 26mDelta
Thu 14/812:00 p.m.LGW - SEA
1 stop18h 53mDelta
Deal found 27/4C$ 990
Sun 27/711:34 a.m.SEA - LGW
1 stop14h 26mMultiple Airlines
Thu 28/812:00 p.m.LGW - SEA
2 stops19h 55mMultiple Airlines
Deal found 27/4C$ 1,001

Cheapflights Fare Finder

Customize your flight search to find flights from Seattle to London that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 29 April 2025.
Use the filters below to find and compare flights from Seattle to London that are best for you.

Fly from

Seattle

Fly to

London

Route

Depart

Return

Price

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 10/9

4:00 p.m.-9:20 a.m.

1 stop33h 20m

London Heathrow

Fri 19/9

6:40 a.m.-2:00 p.m.

1 stop15h 20m

C$ 864

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Fri 26/9

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

1 stop11h 40m

London Gatwick

Sat 4/10

3:40 p.m.-8:40 p.m.

1 stop13h 00m

C$ 878

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 23/9

3:45 p.m.-11:55 a.m.

1 stop12h 10m

London Heathrow

Fri 3/10

1:05 p.m.-5:50 p.m.

1 stop12h 45m

C$ 894

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 3/9

7:20 a.m.-6:30 a.m.

1 stop15h 10m

London Heathrow

Wed 17/9

6:30 a.m.-6:36 p.m.

2 stops20h 06m

C$ 937

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Wed 6/8

5:30 a.m.-10:00 a.m.

2 stops20h 30m

London Gatwick

Tue 19/8

12:00 p.m.-10:53 p.m.

1 stop18h 53m

C$ 941

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 27/8

7:20 a.m.-10:00 a.m.

1 stop18h 40m

London Heathrow

Mon 15/9

8:05 p.m.-6:36 p.m.

2 stops30h 31m

C$ 947

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 23/9

8:25 p.m.-2:15 p.m.

Nonstop9h 50m

London Heathrow

Tue 7/10

6:30 a.m.-11:50 a.m.

1 stop13h 20m

C$ 954

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 23/9

10:00 a.m.-11:50 a.m.

2 stops17h 50m

London Heathrow

Tue 14/10

6:30 a.m.-11:55 a.m.

1 stop13h 25m

C$ 955

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Mon 25/8

4:25 p.m.-5:50 p.m.

1 stop17h 25m

London Gatwick

Wed 10/9

6:35 p.m.-6:36 p.m.

2 stops32h 01m

C$ 969

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 1/9

4:25 p.m.-5:50 p.m.

1 stop17h 25m

London Heathrow

Mon 8/9

8:05 p.m.-6:36 p.m.

2 stops30h 31m

C$ 974

Flights are sorted by cheapest round-trip flights first.

Deals found on 27/4

Showing 1-10 of 40 results
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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
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

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

Use this chart to determine the optimal time to book a round-trip flight from Seattle to London. Price data was last updated on 25 April 2025.

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 75 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

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$ 560). Flying from Seattle to London in July is currently the most expensive (average of C$ 870). 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?

Find hourly flight availability from Seattle to London. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 29 April 2025.

It’s optimal to fly from Seattle to London in the morning. By choosing this option you can save up to 29% on the cost of your flight, compared to a flight in the afternoon.

Weekly flight availability from Seattle to London

Explore weekly flight availability from Seattle to London. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated 29 April 2025.

The most flights from SEA to LON are scheduled on a Monday (22 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (16 on average).

Rainfall in London by month

Plan your trip to London by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in London ranges from 40.0 - 70.0 mm per month. January is typically the wettest month, when rainfall can reach 70.0 mm. July is typically the driest time to visit London when rainfall is around 40.0 mm.

Temperature in London by month

Plan your trip to London by taking into account the average temperature totals by month.

If weather is an important factor for your trip to London, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 17.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 4.0 C).

Reviews of airlines servicing London

Get insights into the airlines that provide service to London. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to London. Reviews last updated 29 April 2025.
To help decide which airline to fly from Seattle to London, see what other customers have to say about Delta, Alaska Airlines and SWISS. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
7,929 reviews
Check prices

Comfort

7.9

Food

7.3

Boarding

8.2

Entertainment

7.9

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Delta
8.0
Very good
7,929 reviews
Delta
8.0
Very good
7,929 reviews
Check prices

Comfort

7.9

Food

7.3

Boarding

8.2

Entertainment

7.9

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Alaska Airlines
8.0
Very good
9,961 reviews
Delta
8.0
Very good
7,929 reviews
Check prices

Comfort

7.9

Food

7.3

Boarding

8.2

Entertainment

7.9

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
SWISS
7.5
Good
1,588 reviews
Delta
8.0
Very good
7,929 reviews
Check prices

Comfort

7.9

Food

7.3

Boarding

8.2

Entertainment

7.9

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
United Airlines
7.4
Good
8,696 reviews
Delta
8.0
Very good
7,929 reviews
Check prices

Comfort

7.9

Food

7.3

Boarding

8.2

Entertainment

7.9

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Virgin Atlantic
7.4
Good
642 reviews
Delta
8.0
Very good
7,929 reviews
Check prices

Comfort

7.9

Food

7.3

Boarding

8.2

Entertainment

7.9

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Related info for your journey

Find useful and relevant information for your journey from Seattle to London. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • 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 5 airlines. Seattle/Tacoma Intl is conveniently located just 18.4 km from Seattle’s city centre.

  • What are the cheapest airlines flying from Seattle to London round-trip?

    According to our current data, Scandinavian Airlines (C$ 864), Icelandair (C$ 878), and United Airlines (C$ 937) offers the cheapest pricing from Seattle to London. These flights start at 21% lower than the current average price 3 months from now.

  • What are the cheapest airlines to fly from Seattle to London one-way?

    C$ 403 is the cheapest one-way deal found within the past few days, from Icelandair. You may also be able to find cheap deals on WestJet and Lufthansa, with prices starting from C$ 556 and C$ 579, respectively.

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

    The top 3 most reliable airlines when flying from Seattle to London are Scandinavian Airlines (90%), KLM (85%) and Aeromexico (85%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 428. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 1,066 on average our data indicates C$ 3,077 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$ 560). Flying from Seattle to London in July is currently the most expensive (average of C$ 870). 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 Seattle?

Book flights to Seattle if you plan to visit one of these locations
Brentford
Hounslow
Sutton
Slough
Milton Keynes
Romford
Watford
Luton
Bromley
Bedford
Southall

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Alternative routes for Seattle to London

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to Heathrow flights
Seattle to Manchester flights
Seattle to Gatwick flights

Top 5 airlines flying from Seattle to London

Discover the top 5 airlines that operate flights from Seattle to London. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 29 April 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 610AverageC$ 799FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
IberiaCheapestC$ 632AverageC$ 846FlexibilityNo cancel feeOn-time77%
Search Iberia flights
Virgin AtlanticCheapestC$ 794AverageC$ 1,019FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
KLMCheapestC$ 808AverageC$ 952FlexibilityNo cancel feeOn-time75%
Search KLM flights
British AirwaysCheapestC$ 855AverageC$ 1,192FlexibilityNo cancel feeOn-time70%
Search British Airways flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

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.

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