Dulles (IAD) to Seattle (SEA)
Flight time
≈ 5h 24m
Bearing
300° NW
Dulles (IAD) to Seattle (SEA) is 2,300 miles (3,702 km) as the crow flies — the great-circle baseline most distance-based mileage programs credit.
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What actually flies IAD–SEA
Filed traffic dataIn July 2026, Alaska Airlines operated the most departures, one of 3 carriers flying nonstop IAD–SEA; the Boeing 737 MAX 9 was the most common aircraft at 42% of departures; flights ran 94% full.
Departures
421
July 2026
Seats
71,014
both directions
Passengers
66,519
both directions
Load factor
93.7%
RPM ÷ ASM
Who flies IAD–SEA?
Alaska Airlines operated the most nonstop IAD–SEA departures in July 2026 (182), one of 3 carriers on the route.
- AS
182 departures · 32,260 seats
Share of departures43.2%93.5%
Load
- UA
177 departures · 30,695 seats
Share of departures42.0%94.5%
Load
- DL
62 departures · 8,059 seats
Share of departures14.7%91.4%
Load
What plane flies IAD–SEA?
In July 2026, the Boeing 737 MAX 9 flew 42% of IAD–SEA departures — more than any other aircraft type.
- Boeing 737 MAX 9
176 departures · 94.2% load
41.8% - Boeing 737-900ER
99 departures · 93.2% load
23.5% - Airbus A220-300
62 departures · 91.4% load
14.7% - Boeing 737-800
46 departures · 95.5% load
10.9% - Boeing 737 MAX 8
38 departures · 93.0% load
9.0%
How has IAD–SEA traffic changed?
Nonstop IAD–SEA departures fell from 442 in August 2025 to 421 in July 2026.
Monthly nonstop IAD–SEA traffic, trailing 12 months through July 2026. Bars scale to the busiest month; months with no filed service show as zero.
August 2025
442 departures · 68,434 passengers
91.5%
Load
September 2025
358 departures · 48,442 passengers
80.5%
Load
October 2025
307 departures · 40,228 passengers
79.2%
Load
November 2025
234 departures · 29,724 passengers
78.5%
Load
December 2025
249 departures · 35,376 passengers
86.2%
Load
January 2026
199 departures · 25,424 passengers
78.7%
Load
February 2026
186 departures · 23,870 passengers
79.0%
Load
March 2026
229 departures · 33,525 passengers
89.6%
Load
April 2026
255 departures · 37,033 passengers
87.0%
Load
May 2026
403 departures · 57,716 passengers
85.6%
Load
June 2026
392 departures · 60,211 passengers
91.0%
Load
July 2026
421 departures · 66,519 passengers
93.7%
Load
By direction
Each direction is filed separately — they rarely match.
SEA → IAD
92.7% full
211 departures · 32,813 passengers
IAD → SEA
94.7% full
210 departures · 33,706 passengers
Nonstop IAD–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 Dulles (IAD) from Seattle (SEA)?
IAD to SEA is 2,300 miles (3,702 km / 1,999 nautical miles) measured great-circle — the shortest path over the surface of the Earth.
How long is the flight from IAD to SEA?
A nonstop covers the 2,300-mile great-circle distance in roughly 5h 24m of block time, before winds. Actual schedules vary a few percent by direction and aircraft.
What plane flies IAD–SEA?
In July 2026, the Boeing 737 MAX 9 flew the largest share of departures (41.8%), followed by the Boeing 737-900ER (23.5%).
What mileage do I earn flying IAD–SEA?
Distance-based programs credit off the 2,300-mile great-circle figure, then apply your fare-class earning rate. Revenue-based programs credit off the fare instead.
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