Expect long security lines at Heathrow. Ensure all liquids are in one small bag to avoid delays during manual screening.

Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $595 (Gotogate) |
One-way from | $542 (Cheapflightsfares) |
Popular in | December |
Cheapest in | February |
Average price | $756 |
Good round-trip deal | $775 or less |
Good one-way deal | $656 or less |
Fly from
Fly to
Route
Depart
Return
Price
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Wed 12/24
6:30 am-6:26 pm
2 stops19h 56m
Seattle/Tacoma Intl
Mon 12/29
12:55 am-7:05 am
1 stop22h 10m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Wed 3/18
6:30 am-12:35 pm
1 stop13h 05m
Seattle/Tacoma Intl
Wed 3/25
5:40 pm-10:30 am
Nonstop9h 50m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Mon 12/29
6:30 am-8:44 pm
2 stops22h 14m
Seattle/Tacoma Intl
Thu 3/19
7:50 am-10:15 am
2 stops19h 25m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Mon 12/29
6:30 am-6:26 pm
2 stops19h 56m
Seattle/Tacoma Intl
Thu 3/5
4:45 pm-10:30 am
Nonstop9h 45m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Fri 12/26
6:30 am-11:50 am
1 stop13h 20m
Seattle/Tacoma Intl
Tue 12/30
7:20 pm-12:50 pm
Nonstop9h 30m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Thu 11/27
12:15 pm-5:00 pm
1 stop12h 45m
Seattle/Tacoma Intl
Mon 12/1
2:35 pm-7:30 pm
1 stop20h 55m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Tue 3/10
6:30 am-1:10 pm
1 stop13h 40m
Seattle/Tacoma Intl
Tue 3/17
8:30 am-9:10 am
2 stops17h 40m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Fri 12/26
12:20 pm-2:58 pm
Nonstop10h 38m
Seattle/Tacoma Intl
Wed 12/31
4:48 pm-10:30 am
Nonstop9h 42m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Mon 12/29
9:40 am-10:45 am
1 stop33h 05m
Seattle/Tacoma Intl
Tue 3/17
8:20 pm-12:50 pm
Nonstop9h 30m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Wed 3/18
6:35 am-9:17 pm
2 stops21h 42m
Seattle/Tacoma Intl
Wed 3/25
7:00 am-6:40 am
2 stops16h 40m
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*1 star | |
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*1 star |
The best time to book flights from London Heathrow Airport to Seattle is 76 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
Currently, January is the cheapest month in which you can book a flight from London Heathrow Airport to Seattle (average of $474). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of $673). 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 London Heathrow Airport to Seattle is to remain as flexible as possible. Flights that are in the evening tend to be the most expensive. A flight at noon could potentially save you up to 10% on airfare.
Travelers seeking maximum savings on their London Heathrow Airport to Seattle flight should consider departing on Sunday evenings when fares are most often at their lowest. Friday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.
About 15% of weekly flights between London and Seattle have experienced delays in the past year, with the average delay time being 127 minutes.
Historically, flights departing in the evening are less likely to be delayed, whereas flights leaving in the early afternoon tend to experience delays more often.
Sunday tends to have the lowest number of delays on this route, whereas Wednesday has historically faced a higher average of delays compared to other days of the week.
Over the last year, Scandinavian Airlines have had the lowest number of delays on this route, with just 4% of flights being delayed.
Food
Comfort
Crew
Boarding
Overall
Entertainment
Reviews
Mary,Oct 2025
AMS - PDX
Food
Comfort
Crew
Boarding
Overall
Entertainment
Reviews
Mary,Oct 2025
AMS - PDX
Food
Comfort
Crew
Boarding
Overall
Entertainment
Reviews
Mary,Oct 2025
AMS - PDX
Food
Comfort
Crew
Boarding
Overall
Entertainment
Reviews
Mary,Oct 2025
AMS - PDX
Food
Comfort
Crew
Boarding
Overall
Entertainment
Reviews
Mary,Oct 2025
AMS - PDX
Food
Comfort
Crew
Boarding
Overall
Entertainment
Reviews
Mary,Oct 2025
AMS - PDX
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$497 | Average$644 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$560 | Average$760 | FlexibilityNo cancel fee | On-time70% | |
| Cheapest$589 | Average$813 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$594 | Average$906 | FlexibilityNo cancel fee | On-time72% | |
| Cheapest$600 | Average$825 | FlexibilityNo cancel fee | On-timeN/A |