Cheap flights from Seattle to London from £158
This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Seattle to London departing on 8/10. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
Discover deals from 900+ travel sites with momondo.
Save money when you book flights with momondo
Big names, great deals
Big names, great deals
Search 100s of travel sites to compare prices.Filter for what you want
Filter for what you want
Free Wi-Fi? Stopover? Instantly customise your results.Trusted and free
Trusted and free
We’re completely free to use - no hidden charges or fees.Price Alerts
Price Alerts
Not ready to book? to track prices.Find the cheapest flights from Seattle to London
Cheap return flights
Cheap one-way flights
Cheap last-minute flights
Cheap direct flights
Scandinavian Airlines flights from Seattle to London Heathrow Airport
Our best Scandinavian Airlines deals on Seattle to London Heathrow Airport flight tickets
Aer Lingus flights from Seattle to London Heathrow Airport
Our best Aer Lingus deals on Seattle to London Heathrow Airport flight tickets
See travel insights to London from
How to get the cheapest flight ticket from Seattle to London Heathrow Airport
Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip
What is the cheapest month to fly to London Heathrow Airport?
In general, March is the cheapest month to fly from Seattle to London Heathrow Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around £503. The month of April is another great option to travel to London Heathrow Airport, with average flight prices from Seattle averaging around £512.
What is the cheapest day to depart on your flight to London Heathrow Airport?
On average, the least expensive day to fly to London Heathrow Airport from Seattle is on a Tuesday. momondo users have found tickets for Tuesday departures for as low as £566. However, this price may fluctuate depending on the airline, the season, and holidays. Be sure to avoid booking your departure on a Thursday as prices are generally higher than usual. According to our data, the average ticket price to London Heathrow Airport on Thursday is £778.
What is the cheapest time of day to depart on your flight to London Heathrow Airport?
According to our data, the cheapest time of day to fly to London Heathrow Airport is in the afternoon. momondo users have found flights departing from Seattle to London Heathrow Airport in the afternoon for as low as £630. Keep in mind that these prices may fluctuate based on what airline you choose and the time of year you plan to travel. If you have a flexible travel schedule, then try to avoid flying at midday when prices are £680 on average. Flights to London Heathrow Airport from Seattle at midday are generally more expensive because this time of day is more convenient for travellers’ schedules.
What is the cheapest Seattle/Tacoma Intl to London Heathrow flight route?
Fly from Seattle/Tacoma Intl to London Heathrow for the best Seattle/Tacoma Intl - London Heathrow flight prices
How far in advance should I book a flight to London Heathrow Airport?
You are more likely to see cheaper flights to London Heathrow Airport from Seattle when booking 9 weeks ahead of your departure date. In general, you can expect to find flights to London Heathrow Airport for around £598 when searching 9 weeks out.However, flight prices might be lower outside of this timeframe. For example, people recently found flights to London Heathrow Airport from Seattle for as low as £545 on momondo.
What cabin class options are available on Seattle/Tacoma Intl to London Heathrow flights?
There are 3 cabin classes available to choose from on Seattle/Tacoma Intl to London Heathrow flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.
What is the cheapest airline that flies from Seattle/Tacoma Intl to London Heathrow?
Icelandair, WestJet, and JetBlue are the most popular carriers operating from Seattle/Tacoma Intl to London Heathrow
Which airlines fly to London Heathrow Airport?
Virgin Atlantic, British Airways and Icelandair are the top three most popular airlines that fly to London Heathrow Airport from Seattle according to our data. Virgin Atlantic is the first choice among our users, with 53% of people opting to fly with this airline when travelling to London Heathrow Airport. Keep in mind that there are 3 different airlines that fly to London Heathrow Airport on a routine basis, so you have a few additional options to choose from.
How many flights depart from Seattle to London Heathrow Airport on average per day?
As of June 2025, 21 flights take off from Seattle and land in London Heathrow Airport each day. The most common flight departure time for this route is 20:00, with 50% of daily flights taking off in the afternoon.
How many flights depart from Seattle to London Heathrow Airport on average per week?
148 flights are operational weekly from Seattle to London Heathrow Airport as of June 2025. The most popular departure day for this route is Mon, with 15% of flights per week taking off on this day.
When to book flights from Seattle to London Heathrow Airport
Cheap Seattle to London Heathrow Airport (SEA to LHR) flight deals and tips
Find info about flight duration, direct flights, and airports for your flight from Seattle to London Heathrow Airport
How far is Seattle/Tacoma Intl to London Heathrow by plane?
The distance between Seattle/Tacoma Intl and London Heathrow is about 4774.1 mi. By plane, this route typically takes 9h 20m.
When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?
Prices for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport are refreshed on a daily basis.
How many operators does momondo search for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport?
There are 3 operators available for flights from Seattle/Tacoma Intl Airport to London Heathrow Airport as of June 2025.
How old do you have to be to fly from Seattle/Tacoma Intl Airport to London Heathrow Airport?
Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Seattle/Tacoma Intl Airport to London Heathrow Airport.
What documentation or ID do you need to fly to London Heathrow Airport?
The travel and health documents you'll need for your trip to London Heathrow Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at London Heathrow Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.
What is the most popular plane model from Seattle to London Heathrow Airport?
Based on momondo bookings for flights between Seattle and London Heathrow Airport, the leading plane model is Boeing 787-10 Dreamliner, making up 25.85% of the total bookings. Other popular models include Boeing 777-300ER with 22.26%, Airbus A330-900neo with 22.01%, and Boeing 777 with 9.42%.
What is the most popular airline from Seattle to London Heathrow Airport?
momondo data reveals that the most frequently booked airline on the route from Seattle to London Heathrow Airport is Virgin Atlantic, representing 53% of all bookings. The subsequent popular airlines are British Airways at 31% and Icelandair at 16%.
Best airlines flying from Seattle to London Heathrow Airport
Compare and see reviews for airlines that fly from Seattle to London Heathrow Airport with momondo
| Airline | Rating | Free Cancellation | Price | ||
|---|---|---|---|---|---|
| PriceFrom £356 | Free Cancellation | Rating 7.0 499 reviews | |||
| PriceFrom £442 | Free Cancellation | Rating 7.4 652 reviews | |||
| PriceFrom £446 | Free Cancellation | Rating 6.6 7,011 reviews |
Virgin Atlantic Flights From Seattle to London Heathrow Airport
Across 14 Virgin Atlantic flights from Seattle to London Heathrow Airport this week, the average price was £863, with the best Virgin Atlantic deals starting from £601 round-trip. 652 users have rated Virgin Atlantic on momondo, with an average score of 7.4/10.
British Airways Flights From Seattle to London Heathrow Airport
Another popular option for Seattle to London Heathrow Airport flights is British Airways (6.6/10, 7,011 ratings). British Airways flies from Seattle to London Heathrow Airport around 13 times per week, with deals starting from £607 round-trip and rising to an average price of around £989.
Travelling to a place near London?
Book flights to London if you plan to visit one of these locationsWhy use momondo?
Why should I use momondo to find a flight deal from Seattle to London?
To find the flight that best suits your needs, momondo gathers a range of flights from a large pool of different airlines and agents; you can then use our insights and filters to find and book the right flight to London from Seattle.
Can I find flights from Seattle to London with flexible booking policies on momondo?
Flights from Seattle to London with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.
How can momondo help me find flights from Seattle to London?
momondo helps you find the best flight between Seattle and London by providing filters to narrow your choice of flights to those matching your criteria. You can select flights based on numerous factors such as price, departure and landing times, airport and airline.
I’m not ready to book a flight from Seattle to London right now. Can momondo alert me if prices change?
If you are simply researching potential flights to London, momondo offers a useful price alert feature which will track prices for flights to London from Seattle and alert you when they change.