Boston (BOS) to Seattle (SEA)
Flight time
≈ 5h 47m
Bearing
296° NW
Boston (BOS) to Seattle (SEA) is 2,489 miles (4,006 km) as the crow flies — the great-circle baseline most distance-based mileage programs credit.
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What actually flies BOS–SEA
Filed traffic dataIn July 2026, Alaska Airlines operated the most departures, one of 3 carriers flying nonstop BOS–SEA; the Airbus A321neo was the most common aircraft at 36% of departures; flights ran 91% full.
Departures
617
July 2026
Seats
113,115
both directions
Passengers
102,868
both directions
Load factor
90.9%
RPM ÷ ASM
Who flies BOS–SEA?
Alaska Airlines operated the most nonstop BOS–SEA departures in July 2026 (276), one of 3 carriers on the route.
- AS
276 departures · 48,393 seats
Share of departures44.7%92.8%
Load
- DL
224 departures · 43,450 seats
Share of departures36.3%90.9%
Load
- B6
117 departures · 21,272 seats
Share of departures19.0%86.8%
Load
What plane flies BOS–SEA?
In July 2026, the Airbus A321neo flew 36% of BOS–SEA departures — more than any other aircraft type.
- Airbus A321neo
224 departures · 90.9% load
36.3% - Boeing 737-900ER
126 departures · 92.5% load
20.4% - Boeing 737 MAX 9
107 departures · 93.6% load
17.3% - Airbus A321
61 departures · 89.6% load
9.9% - Airbus A320
56 departures · 83.0% load
9.1% - Boeing 737-800
28 departures · 91.1% load
4.5% - Boeing 737 MAX 8
15 departures · 91.9% load
2.4%
How has BOS–SEA traffic changed?
Nonstop BOS–SEA departures rose from 539 in August 2025 to 617 in July 2026.
Monthly nonstop BOS–SEA traffic, trailing 12 months through July 2026. Bars scale to the busiest month; months with no filed service show as zero.
August 2025
539 departures · 94,917 passengers
93.8%
Load
September 2025
457 departures · 75,779 passengers
89.2%
Load
October 2025
451 departures · 72,454 passengers
86.4%
Load
November 2025
320 departures · 48,160 passengers
81.5%
Load
December 2025
315 departures · 47,989 passengers
83.2%
Load
January 2026
245 departures · 36,984 passengers
81.8%
Load
February 2026
242 departures · 35,464 passengers
79.4%
Load
March 2026
341 departures · 52,934 passengers
83.9%
Load
April 2026
342 departures · 53,611 passengers
84.5%
Load
May 2026
506 departures · 81,086 passengers
86.1%
Load
June 2026
549 departures · 88,995 passengers
87.5%
Load
July 2026
617 departures · 102,868 passengers
90.9%
Load
By direction
Each direction is filed separately — they rarely match.
BOS → SEA
90.6% full
310 departures · 51,505 passengers
SEA → BOS
91.3% full
307 departures · 51,363 passengers
Nonstop BOS–SEA traffic has been filed since 2025.
Source: US DOT BTS Form 41 T-100 Segment (All Carriers). Data through July 2026; filings from 2025. Public domain (US Government work).
The airports
Frequently asked
How far is Boston (BOS) from Seattle (SEA)?
BOS to SEA is 2,489 miles (4,006 km / 2,163 nautical miles) measured great-circle — the shortest path over the surface of the Earth.
How long is the flight from BOS to SEA?
A nonstop covers the 2,489-mile great-circle distance in roughly 5h 47m of block time, before winds. Actual schedules vary a few percent by direction and aircraft.
What plane flies BOS–SEA?
In July 2026, the Airbus A321neo flew the largest share of departures (36.3%), followed by the Boeing 737-900ER (20.4%).
What mileage do I earn flying BOS–SEA?
Distance-based programs credit off the 2,489-mile great-circle figure, then apply your fare-class earning rate. Revenue-based programs credit off the fare instead.
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