Nonstop flights from Seattle (SEA) to London (usually LHR) are typically about 9.5 hours in the air , with many schedules falling in roughly the 9–10 hour range.

Quick Scoop

  • Typical nonstop flight time: about 9 hours 20–45 minutes.
  • Published averages:
    • One calculator lists about 9 h 34 min for a standard commercial jet.
* Another service reports around **9 h 18–23 min** as a common block time.

* A dedicated route estimator gives about **9 h 45 min** SEA → LHR based on historical data.
  • With taxiing, minor delays, and boarding, you should plan on around 11–12 hours total “airport to airport” time from first pushback in Seattle to walking off the plane in London (including ground time on both ends), though this can be shorter or longer depending on the day.

What can change the duration?

  • Routing and winds : Flights going east (Seattle to London) often benefit from tailwinds in the jet stream, sometimes shaving a bit of time off the schedule.
  • Aircraft type and cruise speed : Different widebodies (e.g., 787 vs A350 vs 777) can have small differences in block time.
  • Stops vs nonstop :
    • Nonstop SEA → LON is ~9–10 hours.
    • One-stop itineraries (e.g., via Reykjavik, Chicago, or another hub) can easily become 13–20+ hours total once connection time is included.

Simple rule of thumb

If you’re just trying to plan your day, a good rule is:

“Expect about 10 hours in the air, and 11–12 hours total door-to-door between the two airports, assuming a nonstop flight and normal conditions.”

SEO notes

  • Focus keyword: how long is the flight from seattle to london is directly answered with a 9–10 hour nonstop estimate.
  • This route remains a popular transatlantic pairing in 2025–2026, with several major carriers and online travel agencies actively selling and promoting SEA–LON flights.

Information gathered from public forums or data available on the internet and portrayed here.