Flights London → Seattle
LHR → SEA
How long is the flight from London to Seattle?
The flight from London (LHR) to Seattle (SEA) takes 9h 18m on average. That is the median time recorded across 1 scheduled flight on this leg; the actual time varies by a few minutes with wind, routing and take-off queues.
Route overview
This flight route operates between London and Seattle, with a high on-time performance rate of 92%. Over the course of a year, it sees an average of 14 flights, each using either a Boeing 777 or a Boeing 747-400 aircraft. The destination airport in Seattle handles over 52 million passengers annually, indicating significant traffic and connectivity.
The London (LHR) → Seattle (SEA) route is operated by American Airlines, Air France, British Airways, Delta Air Lines, Iberia Airlines, KLM Royal Dutch Airlines. Across 28 flights monitored in recent months, 79% arrived on time (within 15 min of schedule), with an average delay of 6 minutes. The cancellation rate is 0.00%. FlightGuard's average computed risk is 9.2/100 (low), updated in real time from weather, ATC delays, strikes, NOTAMs, fuel and flight history. At Seattle the average ATFM delay is 5.5 minutes (main cause: atfm). Departing from London the average ATFM delay is 1.8 minutes.
Heading to Seattle: what to expect in this direction
Flying from London (LHR) to Seattle (SEA) heads north-west for about 7,702 km, a flight time of roughly 9h 18m.
Departures from London on this leg cluster in the midday window: about 100% of LHR-SEA flights take off then.
Air-traffic congestion: departing London the average ATFM delay is 1.8 min (atfm); arriving into Seattle it is 5.5 min (atfm).
Across 28 tracked LHR-SEA flights, 79% left on time with an average delay of 6 min and a 0.0% cancellation rate.
Route facts
Flexible on this trip? Compare flights
Airline punctuality on this route
| Airline | On-time | Average delay | Cancellations |
|---|---|---|---|
| Iberia Airlines (IB) | 87% | 20 min | 1.2% |
| Delta Air Lines (DL) | 85% | 1 min | 0.8% |
| Air France (AF) | 82% | 28 min | 0.0% |
| KLM Royal Dutch Airlines (KL) | 82% | 19 min | 5.9% |
| American Airlines (AA) | 79% | 6 min | 1.1% |
| British Airways (BA) | 66% | 31 min | 1.3% |
Airlines operating LHR-SEA
Airports
Frequently asked questions about LHR-SEA
The flight from London (LHR) to Seattle (SEA) takes 9h 18m on average. That is the median time recorded across 1 scheduled flight on this leg; the actual time varies by a few minutes with wind, routing and take-off queues.
On the London (LHR) -> Seattle (SEA) route, on-time performance is 79% with an average delay of 6 minutes, based on 28 tracked flights.
The cancellation rate on London-Seattle is 0.00% across 28 monitored flights.
The route is operated by 6 airlines: American Airlines, Air France, British Airways, Delta Air Lines, Iberia Airlines, KLM Royal Dutch Airlines.
Enter your flight number on FlightGuard for a real-time analysis based on 9 factors: weather at Seattle, ATC delays, strikes, NOTAMs, fuel, airline punctuality and recent trends.
The London-Seattle route is about 7,702 km: for a cancellation (with less than 14 days' notice), a delay over 3 hours, or denied boarding, UK261 compensation is £520, barring extraordinary circumstances.
