Plan to arrive at SEA at least two hours before your flight due to potentially long security lines.

Most accurate provider | Mytrip 3 stars |
|---|---|
Most trusted provider | Mytrip 3 stars |
Round-trip from | $521 (Mytrip) |
One-way from | $351 (Kiwi.com) |
Popular in | June |
Cheapest in | October |
Average price | $691 |
Good round-trip deal | $670 or less |
Good one-way deal | $472 or less |
Fly from
Fly to
Route
Depart
Return
Price
SeattleLondon
SEA - STN
SEASTN
Seattle/Tacoma Intl
Wed 12/3
2:35 pm-7:35 pm
2 stops21h 00m
London Stansted
Wed 12/10
6:30 am-5:00 pm
2 stops18h 30m
SeattleLondon
SEA - LTN
SEALTN
Seattle/Tacoma Intl
Tue 12/2
8:10 am-9:45 am
2 stops17h 35m
London Luton
Mon 12/8
7:05 pm-12:10 pm
2 stops25h 05m
SeattleLondon
SEA - LGW
SEALGW
Seattle/Tacoma Intl
Mon 12/29
2:35 pm-10:55 am
1 stop12h 20m
London Gatwick
Tue 3/3
11:55 am-5:00 pm
1 stop13h 05m
SeattleLondon
SEA - LHR
SEALHR
Seattle/Tacoma Intl
Tue 12/9
11:50 am-8:45 am
1 stop12h 55m
London Heathrow
Thu 12/25
6:30 am-11:50 am
1 stop13h 20m
SeattleLondon
SEA - LHR
SEALHR
Seattle/Tacoma Intl
Wed 2/18
4:55 pm-10:30 am
Nonstop9h 35m
London Heathrow
Fri 2/27
6:20 am-1:20 pm
1 stop15h 00m
SeattleLondon
SEA - LHR
SEALHR
Seattle/Tacoma Intl
Mon 1/12
7:20 pm-12:50 pm
Nonstop9h 30m
London Heathrow
Sun 1/18
6:30 am-11:50 am
1 stop13h 20m
SeattleLondon
SEA - LHR
SEALHR
Seattle/Tacoma Intl
Wed 2/11
6:50 pm-12:20 pm
Nonstop9h 30m
London Heathrow
Thu 2/19
2:55 pm-4:55 pm
Nonstop10h 00m
SeattleLondon
SEA - LHR
SEALHR
Seattle/Tacoma Intl
Tue 1/6
6:05 am-7:05 am
1 stop17h 00m
London Heathrow
Tue 1/20
12:20 pm-2:53 pm
Nonstop10h 33m
SeattleLondon
SEA - LHR
SEALHR
Seattle/Tacoma Intl
Tue 12/30
4:48 pm-10:30 am
Nonstop9h 42m
London Heathrow
Wed 3/4
6:30 am-11:35 am
1 stop13h 05m
SeattleLondon
SEA - LHR
SEALHR
Seattle/Tacoma Intl
Tue 12/30
10:05 am-11:50 am
1 stop17h 45m
London Heathrow
Tue 3/3
4:40 pm-1:20 pm
1 stop28h 40m
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*1 star | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*2 stars | |
| Price Accuracy3 stars | Trust Score*2 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars |
Booking 9 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to London. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
Currently, April is the cheapest month in which you can book a flight from Seattle to London (average of $485). Flying from Seattle to London in June is currently the most expensive (average of $792). 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.
One of the essential ways to save on airfare from Seattle to London is to remain as flexible as possible. Flights that are in the morning tend to be the most expensive. A flight in the afternoon could potentially save you up to 25% on airfare.
Travelers seeking maximum savings on their Seattle to London flight should consider departing on Saturday at noon when fares are most often at their lowest. Saturday mornings flights should be avoided if possible as fares are typically the most expensive at this time.
The most flights from SEA to LON are scheduled on a Thursday (20 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (12 on average).
Reykjavik (KEF) – chosen by Cheapflights users on 80% of 1-stop itineraries from Seattle to London on Cheapflights.
Reykjavik (KEF) is the most affordable 1-stop option, with an average round-trip price of $530.
Flights via Dublin (DUB) have the shortest average one-way travel time for 1-stop routes: 11h 35m.
Flights via Reykjavik (KEF) offer the fastest connection on this route, with an average layover time of 1h 29m.
Entertainment
Crew
Food
Comfort
Boarding
Overall
Reviews
Jim,Nov 2025
AVL - ATL
Entertainment
Crew
Food
Comfort
Boarding
Overall
Reviews
Jim,Nov 2025
AVL - ATL
Entertainment
Crew
Food
Comfort
Boarding
Overall
Reviews
Jim,Nov 2025
AVL - ATL
Entertainment
Crew
Food
Comfort
Boarding
Overall
Reviews
Jim,Nov 2025
AVL - ATL
Entertainment
Crew
Food
Comfort
Boarding
Overall
Reviews
Jim,Nov 2025
AVL - ATL
Entertainment
Crew
Food
Comfort
Boarding
Overall
Reviews
Jim,Nov 2025
AVL - ATL
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$465 | Average$871 | FlexibilityNo cancel fee | On-time77% | |
| Cheapest$482 | Average$648 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$500 | Average$703 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$517 | Average$751 | FlexibilityNo cancel fee | On-time77% | |
| Cheapest$518 | Average$846 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$546 | Average$793 | FlexibilityNo cancel fee | On-time70% | |
| Cheapest$547 | Average$782 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$553 | Average$999 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$556 | Average$697 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$562 | Average$833 | FlexibilityNo cancel fee | On-timeN/A |