Q: 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$ 809 and C$ 1,158 in August. The cheapest round-trip price found within the last 3 days was C$ 699 on Delta (24 Aug-5 Sep).

Question 1

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

Accepted Answer

Reykjavik (KEF) is the most affordable 1-stop option, with an average round-trip price of C$ 710.

Question 2

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

Accepted Answer

Reykjavik (KEF) – chosen by Cheapflights users on 78% of one-stop itineraries from Seattle to London on Cheapflights.

Question 3

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

Accepted Answer

Airfare is below average for this route at the moment.Seattle to London flights typically cost between C$ 809 and C$ 1,158 in August.
The cheapest round-trip price found within the last 3 days was C$ 699 on Delta (24 Aug-5 Sep).

Question 4

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

Accepted Answer

Flights via Reykjavik (KEF) have the shortest average one-way travel time for 1-stop routes: 12h 20m.

Question 5

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

Accepted Answer

Flights via Munich (MUC) offer the fastest connection on this route, with an average layover time of 1h 25m.

Question 6

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

Accepted Answer

According to our current data, Icelandair (C$ 573), Virgin Atlantic (C$ 695), and Iberia (C$ 721) offers the cheapest pricing from Seattle to London. These flights start at 45% lower than the current average price 3 months from now.

Question 7

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

Accepted Answer

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

Question 8

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

Accepted Answer

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.

Question 9

What is the cheapest day to fly from Seattle to London?

Accepted Answer

Travelers seeking maximum savings on their Seattle to London flight should consider departing on Sunday at noon when fares are most often at their lowest. Friday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

Question 10

Weekly flight availability from Seattle to London

Accepted Answer

The most flights from SEA to LON are scheduled on a Tuesday (25 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (15 on average).

Question 11

E

Accepted Answer

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.

Question 12

E

Accepted Answer

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).

Question 13

What are the cheapest flights from Seattle to London?

Accepted Answer

Looking at all options, your cheapest flight can be booked for C$ 512. While the most popular route (Seattle/Tacoma Intl - London Heathrow) can be booked for C$ 698 on average our data indicates C$ 1,450 when flying from Seattle to London.

Question 14

What are the most reliable airlines from Seattle to London?

Accepted Answer

The top 3 most reliable airlines when flying from Seattle to London are Aeromexico (90%), KLM (87%) and Air France (87%).

Question 15

What are the most popular airlines that fly from Seattle to London?

Accepted Answer

Consider British Airways, Icelandair or Iberia when booking your flight. These represent the most popular airlines when flying from Seattle to London.

Question 16

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

Accepted Answer

Saturday is generally a great day to depart. Flying on this day could help you save up to 7%.

Question 17

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

Accepted Answer

To save up to 49% on this flight, we recommend booking at least 51 days prior to travel. The price may fluctuate and will likely increase closer to your departure date. Users on Cheapflights have found tickets from Seattle to London from C$ 1,017 1-2 weeks out and tickets from C$ 1,350 for flights departing within the next 72 hours.

Question 18

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

Accepted Answer

October is one of the best times of the year to fly to London from Seattle. Prices for October average C$ 1,046 per person but you can even find prices for as low as C$ 725. The most expensive prices can be found in the month of June. Opting for a October flight can save you 32% on your journey compared to booking in June

Question 19

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

Accepted Answer

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.

Question 20

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

Accepted Answer

Most people fly from Seattle/Tacoma Intl (SEA) if they book a flight from Seattle to London. On average, Seattle/Tacoma Intl has 20 outbound flights to London per day from 4 airlines. Seattle/Tacoma Intl is conveniently located just 18.4 km from Seattle’s city centre.

Question 21

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

Accepted Answer

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

Question 22

How can I find direct flights from Seattle to London?

Accepted Answer

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

Question 23

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

Accepted Answer

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.

Question 24

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

Accepted Answer

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.

Question 25

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

Accepted Answer

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.

Question 26

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

Accepted Answer

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

Question 27

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

Accepted Answer

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.

Round-trip from	C$ 699
One-way from	C$ 332
Popular in	June
Cheapest in	October
Average price	C$ 943
Good round-trip deal	C$ 986 or less
Good one-way deal	C$ 563 or less

Airline	Cheapest	Average	Flexibility	On-time
Icelandair	CheapestC$ 573	AverageC$ 759	FlexibilityNo cancel fee	On-time76%	Search Icelandair flights
Virgin Atlantic	CheapestC$ 695	AverageC$ 967	FlexibilityNo cancel fee	On-time72%	Search Virgin Atlantic flights
Iberia	CheapestC$ 721	AverageC$ 854	FlexibilityNo cancel fee	On-time77%	Search Iberia flights
British Airways	CheapestC$ 822	AverageC$ 1,127	FlexibilityNo cancel fee	On-time70%	Search British Airways flights

Cheap flights from Seattle to London from C$ 332

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 23/9. Fares are subject to change and may not be available on all flights or dates of travel.

Cheapflights Tip: The best prices from Seattle/Tacoma Intl to London are usually found in October or January, booked 50 days in advance, depart on a Sunday or Thursday and return on a Tuesday

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Cheapest flights from Seattle to LondonExplore 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 14 August 2025.

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 14 August 2025.

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

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.

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 8 August 2025.

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

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 14 August 2025.

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 14 August 2025.

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

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

Share of one-stop round-trip flights from Seattle to London chosen by Cheapflights users in the past 12 months, using the same layover each way.

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

Average round-trip fare for 1-stop flights from Seattle to London, chosen by Cheapflights users in the past 12 months, with the same layover each way.

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

Shortest average travel time for 1-stop one-way flights from Seattle to London, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

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

Average layover duration for 1-stop one-way flights from Seattle to London, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Reviews of airlines servicing London

Get a feel of what it's like to fly with KLM,Virgin Atlantic, andIcelandair 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.

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?

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

What are the most reliable airlines from Seattle to London?

What are the cheapest flights from Seattle to London?

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

How can I find direct flights from Seattle to London?

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

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

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Alternative routes for Seattle to London

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Top 4 airlines flying from Seattle to London

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

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

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

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

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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 14 August 2025.