Washington (IAD) – Seattle (SEA)
- Distance
- 3,711 km
- 2,306 mi · 2,004 nm
- Flight time
- 5 h 47 min / 4 h 51 min
- Average gate to gate: IAD → SEA / back
- Time difference
- 3 h
- CO2 per passenger
- 433 kg
- One way, economy, incl. RF (256 kg CO2 only)
- Passengers / year
- 526,378
- Aug 2025 – Jul 2026 · −13.9%
- Flights / week
- 71
- Both directions, average
- Seats filled
- 86%
- 611,541 seats a year
- Airlines nonstop
- 3
- AS, UA, DL
Traffic: U.S. DOT, Bureau of Transportation Statistics, T-100 Segment (all carriers, scheduled service), Aug 2025 – Jul 2026. Distance: WGS-84 ellipsoid. CO2: UK DESNZ 2026 factors. Sources
The way there
- Heading from IAD
- 300°
- Heading from SEA
- 88°
- Halfway point
- 45.45, -98.24
- Great-circle km
- 3,702 km (sphere, for EU261)
- In the air IAD → SEA
- 5 h 14 min
- In the air SEA → IAD
- 4 h 23 min
- Clocks
- Seattle is 3 h behind Washington
The estimate for a route without real times is 5 h 10 min; how it is worked out is on Sources.
Show as a table
| Month | Passengers |
|---|---|
| Aug 2025 | 68,434 |
| Sep 2025 | 48,442 |
| Oct 2025 | 40,228 |
| Nov 2025 | 29,724 |
| Dec 2025 | 35,376 |
| Jan 2026 | 25,424 |
| Feb 2026 | 23,870 |
| Mar 2026 | 33,525 |
| Apr 2026 | 37,033 |
| May 2026 | 57,634 |
| Jun 2026 | 60,169 |
| Jul 2026 | 66,519 |
Show as a table
| Month | Flights |
|---|---|
| Aug 2025 | 442 |
| Sep 2025 | 358 |
| Oct 2025 | 307 |
| Nov 2025 | 234 |
| Dec 2025 | 249 |
| Jan 2026 | 199 |
| Feb 2026 | 186 |
| Mar 2026 | 229 |
| Apr 2026 | 255 |
| May 2026 | 401 |
| Jun 2026 | 391 |
| Jul 2026 | 421 |
Airlines flying IAD–SEA nonstop
| Airline | Flights / week | Share of passengers |
|---|---|---|
| ASAlaska Airlines | 32 | 48% |
| UAUnited Air Lines | 25 | 38% |
| DLDelta Air Lines | 14 | 14% |
Both directions, Aug 2025 – Jul 2026. Airlines with at least one flight a month. U.S. DOT, Bureau of Transportation Statistics, T-100 Segment (all carriers, scheduled service). Sources
Aircraft on this route
- Boeing B737 Max 900 · 1,277 flights
- Boeing 737-900ER · 1,065 flights
- A220-300 BD-500-1A11 · 704 flights
- Boeing B737 Max 800 · 333 flights
- Boeing 737-800 · 273 flights
- A200-100 BD-500-1A10 · 7 flights
- Boeing 737-700/700LR/Max 7 · 6 flights
- Airbus Industrie A319 · 6 flights
Also carried: 313 tonnes of freight and 14 tonnes of mail a year (passenger and cargo flights).
Punctuality
- On time
- 80.6%
- Arrived within 15 min of schedule
- Average delay
- 13 min
- Late arrivals count, early ones as 0
- Cancelled
- 0.8%
- Flights counted
- 3,704
- Aug 2025 – Jul 2026
| Airline | On time | Average delay |
|---|---|---|
| ASAlaska Airlines | 78.8% | 10 min |
| UAUnited Air Lines | 85% | 11 min |
| DLDelta Air Lines | 76.5% | 21 min |
Delay minutes by cause: airline 47% · aircraft arriving late 22% · air traffic system 25% · weather 6% · security 1%.
Both directions, Aug 2025 – Jul 2026. BTS Reporting Carrier On-Time Performance (US domestic flights of the larger US airlines). Sources
What passengers paid
- Average fare, Q1 2026
- $316
- One way, all cabins
- Average over a year
- $316
- Q2 2025 – Q1 2026
- Largest airline
- Alaska Airlines
- 42% of passengers · $295
- Lowest-fare airline
- Alaska Airlines
- 42% of passengers · $295
History, not a price to book: what the average passenger paid per one-way trip in each quarter (Q2 2025 $315 · Q3 2025 $313 · Q4 2025 $325 · Q1 2026 $316).
Fare outlook, Q1 2027: about $323, likely $279–$368
The average fare paid we expect a year after Q1 2026, the newest DOT quarter. On this route, past forecasts made this way fell inside the range 90% of the time over 21 quarters (median error 3.8%). An estimate from US DOT data: not a price you can book, not a guarantee, not advice on when to buy. How the outlook works
Cheapest quarter on this route: Q1, typically 7% below the year's average (9 years of DOT data, without 2020–21).
U.S. DOT Consumer Airfare Report, Table 1a (airline ticket sample, US domestic airport pairs). Sources
Delay compensation (EU261 / UK261)
Measured by great-circle distance: 3,702 km.
Neither EU261 nor UK261 covers this route: it neither starts nor ends in the EU, EEA, Switzerland or the UK. Other countries have their own rules (for example Canada's APPR or Brazil's ANAC rules).
Also owed for a cancellation with less than 14 days' notice or denied boarding. Not owed for extraordinary circumstances. On a connection, the distance to the final destination counts. From 23 October 2027 the EU's Regulation 2026/2202 applies; it keeps these amounts (what changes in 2027). Information, not legal advice.
Every airport pair between Washington and Seattle
Kilometres. Linked numbers have a page of their own. All Washington airports · All Seattle airports
More routes from IAD
More routes from SEA
| Route | Distance | Passengers / year |
|---|---|---|
| SEA → DEN | 1,648 km | 1,819,437 |
| SEA → PHX | 1,781 km | 1,813,338 |
| SEA → LAX | 1,535 km | 1,810,795 |
| SEA → ANC | 2,331 km | 1,694,688 |
| SEA → SFO | 1,092 km | 1,628,228 |
| SEA → ORD | 2,769 km | 1,622,991 |
| SEA → LAS | 1,394 km | 1,596,435 |
| SEA → DFW | 2,671 km | 1,577,921 |
| SEA → SAN | 1,690 km | 1,233,726 |
| SEA → SLC | 1,108 km | 1,106,553 |