Boston to Seattle flights
Routavio compares airline fares from several flight booking sites. The lowest one-way fare it found for Boston to Seattle is €138 with Frontier Airlines (checked on 24 Oct 2026).
Your next trip, last seen at €138
Lowest observedFrontier Airlines · 2 stops · One wayWhen to fly
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The lowest fare we observed for each month. Open a month to see its days, then pick your outbound and return. A day with no price is one we will search for you.
One-way fare
- Lowest observed
- €138, departing 13 Nov 2026 (Last checked: 24 Oct 2026)One-way fare · Priced departure days checked in the last 14 days: 10Check live prices for this route
- Round trip
- €409, departing 26 Nov 2026, back 30 Nov 2026 (Last checked: 30 Oct 2026)
- Non-stop, one way
- €149, departing 4 Nov 2026 (Last checked: 30 Oct 2026)
- Airlines seen
- Alaska Airlines, JetBlue, Delta Air Lines, Allegiant Air, American Airlines, Frontier Airlines, Porter Airlines Canada, Southwest Airlines, Sun Country Airlines, United Airlines (10)
- Reported fastest flight
- 6h 22m
- Non-stop
- Yes
About this route
Explore the fares we observed from Boston to Seattle. Prices move often, so pick your dates to see the latest options.
- Route distance
- 4,000 km
- Reported fastest flight
- 6h 22m
- Alternative airports
- PSM, BFI
Route-level information; individual journeys vary.
Published schedules report non-stop service with Alaska Airlines, JetBlue, Delta Air Lines. Check current timetables.
A clearer picture of your fare
If the observed fare for this date drops, we will email you. At most one message a day.
Non-stop airlines seen on this route
| Airline | Non-stop days / priced days | Fastest non-stop |
|---|---|---|
| Alaska Airlines | 29 / 82 |
Departure days with a non-stop fare checked in the last 14 days. A carrier listed here had a non-stop fare on at least 3 days; schedules may differ.
Airport to city: straight-line distance
- Portsmouth International Airport at Pease (PSM) → Boston, city gazetteer reference point (42.3584, -71.0598): ≈ 82 km.
- King County International Airport - Boeing Field (BFI) → Seattle, city gazetteer reference point (47.6062, -122.3321): ≈ 9 km.
- Seattle–Tacoma International Airport (SEA) → Seattle, city gazetteer reference point (47.6062, -122.3321): ≈ 18 km.
Approximate distances calculated from coordinates, not road distances or travel times. These airports serve the city; they are not confirmed endpoints of an offer.
Lowest one-way fare we saw per airline
Cheapest airline from Boston to Seattle: Frontier Airlines, from €138 (checked 24 Oct 2026).
| Airline | Lowest fare | Priced days |
|---|---|---|
| Frontier Airlines | €138Nov 13, 2026 | 10 |
| JetBlue | €149Nov 10, 2026 | 15 |
| Alaska Airlines | €150Nov 12, 2026 | 53 |
One-way fares checked in the last 14 days. An airline listed here had a fare on at least 3 departure days. Each figure is the lowest we saw, not a guaranteed fare. Connecting itineraries are included; the date is the departure day of that fare.
Frequently asked
How much is a flight from Boston to Seattle?
The lowest fare Routavio has observed is €138, found on 24 Oct 2026. Prices move, so read it as a floor rather than a quote.
When is the cheapest month to fly from Boston to Seattle?
In our observations November 2026 is the cheapest month so far, at €138.
Are there direct flights from Boston to Seattle?
Yes. Published schedules report non-stop flights on this route with Alaska Airlines, JetBlue, Delta Air Lines.
Which airlines fly from Boston to Seattle?
Routavio has seen these carriers on the route: Alaska Airlines, JetBlue, Delta Air Lines, Allegiant Air, American Airlines, Frontier Airlines, Porter Airlines Canada, Southwest Airlines, Sun Country Airlines, United Airlines (10).
How long does the flight from Boston to Seattle take?
Across the 73 fares Routavio observed, the average journey time is 18h 18m, including any stops. Individual departures vary; the fastest observed flight is listed in the route facts above.
How many of the observed Boston to Seattle fares were non-stop?
36 of the 85 fares we observed were non-stop; the rest included at least one stop. That describes our observations, not every flight that operates.
How much is a round trip from Boston to Seattle?
Cheapest round trip: €409, departing 26 Nov 2026, back 30 Nov 2026 (checked 30 Oct 2026).
How much is a non-stop flight from Boston to Seattle?
Cheapest non-stop one-way fare: €149, departing 4 Nov 2026 (checked 30 Oct 2026).
Which airlines had non-stop offers on at least 3 departure dates from Boston to Seattle?
For Boston to Seattle, examples of observed one-way non-stop offers checked within the last 14 days: Alaska Airlines (29). Each number counts distinct departure dates, not weekly flights; check current availability in search.
Which airline has the lowest fare from Boston to Seattle?
Cheapest airline from Boston to Seattle: Frontier Airlines, from €138 (checked 24 Oct 2026).
How observed prices work, what "No data" means and what a fare includes: Read the flight price guide · Price and schedule freshness on Routavio
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Recently observed fares. Prices may change.