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Cheap flights from Seattle to London from C$ 372

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 21/7. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — LON
1 Jul — 8 Jul1
1 adult

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or January, booked 81 days in advance, depart on a Sunday or Tuesday and return on a Tuesday

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 26 June 2025.

Round-trip from

C$ 816

One-way from

C$ 372

Popular in

June

Cheapest in

October

Average price

C$ 1,410

Good round-trip deal

C$ 1,020 or less

Good one-way deal

C$ 581 or less
Virgin Atlantic
  • Virgin Atlantic
  • 27/8-1/9
  • Nonstop
  • 20h 10m total
  • Seattle to London
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Icelandair
  • Icelandair
  • 21/7
  • 1 total stop
  • 12h 00m total
  • Seattle to London
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Highest demand for flights based on searches. 15% potential increase in price (C$ 274 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease (C$ 44 potential savings vs. average RT price).
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Average for round-trip flights in June 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 26 June 2025.

Wed 27/85:35 p.m.SEA - LHR
Nonstop9h 45mVirgin Atlantic
Mon 1/95:25 p.m.LHR - SEA
Nonstop10h 25mVirgin Atlantic
Deal found 26/6C$ 816
Wed 27/88:45 a.m.SEA - LHR
1 stop16h 55mUnited Airlines
Mon 1/96:50 a.m.LHR - SEA
2 stops21h 52mUnited Airlines
Deal found 26/6C$ 822
Sun 28/97:20 a.m.SEA - LHR
1 stop16h 45mDelta
Sat 11/105:25 p.m.LHR - SEA
Nonstop10h 25mDelta
Deal found 26/6C$ 823
Wed 3/91:30 p.m.SEA - LHR
Nonstop9h 20mBritish Airways
Wed 17/94:30 p.m.LHR - SEA
Nonstop9h 50mBritish Airways
Deal found 25/6C$ 824
Wed 16/78:25 p.m.SEA - LHR
Nonstop9h 50mMultiple Airlines
Tue 22/76:30 a.m.LHR - SEA
1 stop17h 20mMultiple Airlines
Deal found 25/6C$ 829
Mon 28/71:30 p.m.SEA - LHR
Nonstop9h 20mFinnair
Mon 11/89:30 a.m.LHR - SEA
1 stop14h 30mFinnair
Deal found 26/6C$ 834
Tue 5/85:30 a.m.SEA - LGW
2 stops20h 30mVirgin Atlantic
Sun 10/812:00 p.m.LGW - SEA
1 stop18h 48mVirgin Atlantic
Deal found 26/6C$ 845
Thu 4/97:00 a.m.SEA - LHR
2 stops42h 00mAustrian Airlines
Mon 22/97:30 p.m.LHR - SEA
2 stops33h 12mAustrian Airlines
Deal found 25/6C$ 850
Tue 11/1110:05 a.m.SEA - LHR
2 stops16h 05mLufthansa
Tue 18/116:30 a.m.LHR - SEA
1 stop13h 40mLufthansa
Deal found 26/6C$ 856
Tue 16/91:05 p.m.SEA - LGW
2 stops20h 45mSWISS
Sun 5/106:40 p.m.LGW - SEA
2 stops31h 56mSWISS
Deal found 25/6C$ 863
Thu 4/122:35 p.m.SEA - LGW
1 stop12h 20mIcelandair
Mon 15/1211:55 a.m.LGW - SEA
1 stop13h 05mIcelandair
Deal found 25/6C$ 864
Mon 1/94:25 p.m.SEA - LHR
1 stop17h 25mSWISS
Wed 17/98:05 p.m.LHR - SEA
2 stops30h 31mSWISS
Deal found 25/6C$ 871

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 26 June 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 27/8

8:45 a.m.-9:40 a.m.

1 stop16h 55m

London Heathrow

Mon 1/9

6:50 a.m.-8:42 p.m.

2 stops21h 52m

C$ 822

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Sun 28/9

7:20 a.m.-8:05 a.m.

1 stop16h 45m

London Heathrow

Sat 11/10

5:25 p.m.-7:50 p.m.

Nonstop10h 25m

C$ 823

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 3/9

8:20 p.m.-1:40 p.m.

Nonstop9h 20m

London Heathrow

Tue 16/9

9:25 a.m.-11:10 a.m.

Nonstop9h 45m

C$ 824

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Wed 16/7

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

Nonstop9h 50m

London Heathrow

Tue 22/7

6:30 a.m.-3:50 p.m.

1 stop17h 20m

C$ 829

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Mon 28/7

1:30 p.m.-6:50 a.m.

Nonstop9h 20m

London Heathrow

Mon 11/8

9:30 a.m.-4:00 p.m.

1 stop14h 30m

C$ 834

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 5/8

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

2 stops20h 30m

London Gatwick

Sun 10/8

12:00 p.m.-10:48 p.m.

1 stop18h 48m

C$ 845

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 4/9

7:00 a.m.-9:00 a.m.

2 stops42h 00m

London Heathrow

Mon 22/9

7:30 p.m.-8:42 p.m.

2 stops33h 12m

C$ 850

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Tue 11/11

10:05 a.m.-10:10 a.m.

2 stops16h 05m

London Heathrow

Tue 18/11

6:30 a.m.-12:10 p.m.

1 stop13h 40m

C$ 856

SeattleLondon

SEA - LHR

SEALHR

Seattle/Tacoma Intl

Thu 24/7

7:45 a.m.-6:45 a.m.

1 stop15h 00m

London Heathrow

Thu 31/7

6:30 a.m.-3:50 p.m.

1 stop17h 20m

C$ 857

SeattleLondon

SEA - LGW

SEALGW

Seattle/Tacoma Intl

Tue 16/9

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

2 stops20h 45m

London Gatwick

Sun 5/10

6:40 p.m.-6:36 p.m.

2 stops31h 56m

C$ 863

Flights are sorted by cheapest round-trip flights first.

Deals found on 25/6

Showing 1-10 of 44 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 20 June 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 81 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$ 856). 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 26 June 2025.

It’s optimal to fly from Seattle to London in the morning. By choosing this option you can save up to 28% 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 26 June 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 (11 on average).

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 26 June 2025.
Get a feel of what it's like to fly with Delta,Alaska Airlines, andKLM 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.
Delta
8.0
Very good
7,964 reviews
Check prices

Overall

8.0

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Delta
8.0
Very good
7,964 reviews
Delta
8.0
Very good
7,964 reviews
Check prices

Overall

8.0

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Alaska Airlines
8.0
Very good
10,000 reviews
Delta
8.0
Very good
7,964 reviews
Check prices

Overall

8.0

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
KLM
7.8
Good
1,365 reviews
Delta
8.0
Very good
7,964 reviews
Check prices

Overall

8.0

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Austrian Airlines
7.6
Good
805 reviews
Delta
8.0
Very good
7,964 reviews
Check prices

Overall

8.0

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!
Finnair
7.6
Good
1,298 reviews
Delta
8.0
Very good
7,964 reviews
Check prices

Overall

8.0

Entertainment

7.9

Comfort

7.9

Boarding

8.2

Food

7.3

Crew

8.5

Reviews

1 / 20
10.0
Excellent

Kim,May 2025

PIH - SLC

This trip was fine even with delay I had plenty of time to get connection flight!

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 19 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, Virgin Atlantic (C$ 816), Delta (C$ 823), and British Airways (C$ 824) offers the cheapest pricing from Seattle to London. These flights start at 23% lower than the current average price 3 months from now.

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

    C$ 372 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 JetBlue, with prices starting from C$ 455 and C$ 504, respectively.

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

    The top 3 most reliable airlines when flying from Seattle to London are Aeromexico (92%), KLM (88%) and Air France (88%).

  • What are the cheapest flights from Seattle to London?

    Looking at all options, your cheapest flight can be booked for C$ 437. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 972 on average our data indicates C$ 1,455 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$ 856). 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
Sutton
Hounslow
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 Manchester flights
Seattle to Heathrow 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 26 June 2025.
AirlineCheapestAverageFlexibilityOn-time
IcelandairCheapestC$ 603AverageC$ 789FlexibilityNo cancel feeOn-time76%
Search Icelandair flights
IberiaCheapestC$ 624AverageC$ 848FlexibilityNo cancel feeOn-time77%
Search Iberia flights
Virgin AtlanticCheapestC$ 784AverageC$ 997FlexibilityNo cancel feeOn-time72%
Search Virgin Atlantic flights
KLMCheapestC$ 798AverageC$ 846FlexibilityNo cancel feeOn-time75%
Search KLM flights
British AirwaysCheapestC$ 816AverageC$ 1,042FlexibilityNo 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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