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Cheap flights from Seattle to London from $350

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 3/24. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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Find the cheapest flights from Seattle to London

Cheap round-trip flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
2:35 pm - 5:05 pm
SEA
-
SEN
18h 30m2 stops
Multiple Airlines Logo
7:15 am - 5:00 pm
SEN
-
SEA
17h 45m2 stops
$640Multiple Airlines
Sat, Jan 24 - Mon, Feb 2

momondo Fare Finder

 
Customize your flight search to find flights from Seattle to London Southend Airport 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, momondo users made 832,500 searches. Data last updated December 25, 2025.
Use the filters below to find and compare flights from Seattle to London Southend Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Sat 1/24

2:35 pm-5:05 pm

2 stops18h 30m

London Southend

Mon 2/2

7:15 am-5:00 pm

2 stops17h 45m

$640

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Tue 3/24

3:35 pm-10:55 pm

3 stops24h 20m

$350

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Sun 3/22

9:05 pm-11:00 pm

3 stops18h 55m

$352

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Wed 1/21

2:35 pm-11:00 pm

3 stops24h 25m

$357

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Wed 4/15

6:45 pm-11:55 am

2 stops33h 10m

$363

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Thu 1/15

2:35 pm-9:25 pm

3 stops22h 50m

$368

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Thu 1/15

2:35 pm-9:25 pm

3 stops22h 50m

$370

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Mon 2/23

10:53 am-7:45 pm

2 stops24h 52m

$398

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Fri 1/9

2:35 pm-8:50 pm

3 stops46h 15m

$405

SeattleLondon

SEA - SEN

SEASEN

Seattle/Tacoma Intl

Tue 12/30

2:35 pm-10:45 pm

3 stops24h 10m

$407

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 11 resultsSorted by cheapest first
1
2

When to book flights from Seattle to London Southend Airport

Are you open to changing your travel dates? Check out the ideal times to fly from Seattle to London Southend Airport according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Seattle to London Southend Airport (SEA to SEN) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Seattle to London Southend Airport

Fastest flight time

18h 30m

Direct flights

None
The fastest flight from Seattle to London Southend Airport takes 18h 30m
There are no direct flights from Seattle to London Southend Airport. There are no popular flight routes from Seattle to London Southend Airport.
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  • How far is Seattle/Tacoma Intl to London Southend by plane?

    There are 4798.7 mi between Seattle/Tacoma Intl and London Southend. Typically, this will take 18h 30m by plane in normal conditions.

  • When did momondo last update prices for flights from Seattle/Tacoma Intl Airport to London Southend Airport?

    Prices for flights from Seattle/Tacoma Intl Airport to London Southend Airport are updated daily.

  • How old do you have to be to fly from Seattle/Tacoma Intl Airport to London Southend Airport?

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Seattle/Tacoma Intl Airport to London Southend Airport.

  • What documentation or ID do you need to fly to London Southend Airport?

    The travel and health documents you'll need for your trip to London Southend 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 Southend Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.

  • How do I get Price Alerts for flights from Seattle to London Southend Airport?

    Confirm your travel details to search for the latest offers for flights from Seattle to London Southend Airport. While browsing offers there will be the option to toggle “Price Alerts”. You’ll then receive updates when prices for the flight route increase or decrease.

  • How can I save money on flights from Seattle to London Southend Airport with momondo?

    Leverage our AI within our “Price Forecast” tool, which predicts if it’s better to book now or wait until prices decrease. You can strategically pick the best days to fly and save money on your trip by using our “Price Calendar” tool. “Explore” shows an overview of how much it costs to fly to anywhere from a selected city or airport. Our “Discover” content is a great option for travel inspiration and money-saving tips, while “Price Alerts” will update you when prices change, so you can book when fares are right.

  • How does momondo find its flight prices?

    We show prices from over 700+ competitors with a single click. With options from airlines and OTAs from across our 30 international markets, we are able to show you a diverse range of deals to create your adventure.

Traveling to a place near London?

Book flights to London if you plan to visit one of these locations
Gatwick
Hounslow
Milton Keynes
Dover
Luton
Slough
Guildford
Hayes
Dartford
Crawley
Brentwood
Watford
Wembley
Cobham
Folkestone
Romford
Richmond
Uxbridge
Chelmsford
Stansted

Why 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?

momondo does allow users to show only those flights to London from Seattle which offer a flexible booking policy as well as other useful filters and features.

How can momondo help me find flights from Seattle to London?

momondo provides multiple filters to help you find the best flight to London from Seattle. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

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.

An easier way to manage your London Southend Airport trip

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