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

Most accurate provider | eDreams 3 stars |
|---|---|
Most trusted provider | eDreams 3 stars |
Round-trip from | $626 |
One-way from | $532 (Cheapflightsfares) |
Popular in | July |
Cheapest in | February |
Average price | $932 |
Good round-trip deal | $793 or less |
Good one-way deal | $713 or less |
Fly from
Fly to
Route
Depart
Return
Price
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Fri 2/13
2:55 pm-4:55 pm
Nonstop10h 00m
Seattle/Tacoma Intl
Thu 2/19
7:15 am-8:15 am
1 stop17h 00m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Tue 3/3
6:30 am-11:35 am
1 stop13h 05m
Seattle/Tacoma Intl
Thu 3/19
11:47 am-7:05 am
1 stop12h 18m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Sun 3/1
8:40 am-11:35 am
1 stop34h 55m
Seattle/Tacoma Intl
Thu 3/19
7:25 pm-11:55 am
Nonstop9h 30m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Thu 3/5
6:30 am-11:35 am
1 stop13h 05m
Seattle/Tacoma Intl
Thu 3/19
11:47 am-7:05 am
1 stop12h 18m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Wed 3/4
6:35 am-1:20 pm
1 stop14h 45m
Seattle/Tacoma Intl
Tue 3/17
7:00 am-6:40 am
2 stops16h 40m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Wed 3/4
2:55 pm-4:55 pm
Nonstop10h 00m
Seattle/Tacoma Intl
Mon 3/16
7:50 pm-12:20 pm
Nonstop9h 30m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Sat 3/7
9:25 am-11:30 am
Nonstop10h 05m
Seattle/Tacoma Intl
Tue 3/17
7:50 pm-12:20 pm
Nonstop9h 30m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Wed 3/4
2:55 pm-4:55 pm
Nonstop10h 00m
Seattle/Tacoma Intl
Sun 3/15
7:50 pm-12:20 pm
Nonstop9h 30m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Wed 3/4
10:05 am-7:31 pm
1 stop17h 26m
Seattle/Tacoma Intl
Sat 3/14
7:50 pm-12:20 pm
Nonstop9h 30m
LondonSeattle
LHR - SEA
LHRSEA
London Heathrow
Mon 1/26
10:35 am-7:50 pm
1 stop17h 15m
Seattle/Tacoma Intl
Sun 2/8
6:50 pm-12:20 pm
Nonstop9h 30m
| 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*2 stars | |
| 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 62 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 $484). Flying from London Heathrow Airport to Seattle in July is currently the most expensive (average of $679). 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 in the afternoon could potentially save you up to 13% 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 13% of weekly flights between London and Seattle have experienced delays in the past year, with the average delay time being 117 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.
Tuesday 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, Delta have had the lowest number of delays on this route, with just 6% of flights being delayed.
Boarding
Comfort
Crew
Overall
Food
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Boarding
Comfort
Crew
Overall
Food
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Boarding
Comfort
Crew
Overall
Food
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Boarding
Comfort
Crew
Overall
Food
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
Boarding
Comfort
Crew
Overall
Food
Entertainment
Reviews
Jim,Nov 2025
AVL - ATL
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$553 | Average$751 | FlexibilityNo cancel fee | On-time70% | |
| Cheapest$574 | Average$869 | FlexibilityNo cancel fee | On-time72% | |
| Cheapest$589 | Average$854 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$594 | Average$825 | FlexibilityNo cancel fee | On-timeN/A |