Boston (BOS) – Seattle (SEA)
- Distance
- 4,016 km
- 2,496 mi · 2,169 nm
- Flight time
- 6 h 19 min / 5 h 17 min
- Average gate to gate: BOS → SEA / back
- Time difference
- 3 h
- CO2 per passenger
- 469 kg
- One way, economy, incl. RF (277 kg CO2 only)
- Passengers / year
- 791,241
- Aug 2025 – Jul 2026 · −3.7%
- Flights / week
- 95
- Both directions, average
- Seats filled
- 87%
- 912,217 seats a year
- Airlines nonstop
- 3
- AS, DL, B6
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 BOS
- 296°
- Heading from SEA
- 79°
- Halfway point
- 47.88, -95.45
- Great-circle km
- 4,006 km (sphere, for EU261)
- In the air BOS → SEA
- 5 h 41 min
- In the air SEA → BOS
- 4 h 44 min
- Clocks
- Seattle is 3 h behind Boston
The estimate for a route without real times is 5 h 30 min; how it is worked out is on Sources.
Show as a table
| Month | Passengers |
|---|---|
| Aug 2025 | 94,917 |
| Sep 2025 | 75,779 |
| Oct 2025 | 72,454 |
| Nov 2025 | 48,160 |
| Dec 2025 | 47,989 |
| Jan 2026 | 36,984 |
| Feb 2026 | 35,464 |
| Mar 2026 | 52,934 |
| Apr 2026 | 53,611 |
| May 2026 | 81,086 |
| Jun 2026 | 88,995 |
| Jul 2026 | 102,868 |
Show as a table
| Month | Flights |
|---|---|
| Aug 2025 | 539 |
| Sep 2025 | 457 |
| Oct 2025 | 451 |
| Nov 2025 | 320 |
| Dec 2025 | 315 |
| Jan 2026 | 245 |
| Feb 2026 | 242 |
| Mar 2026 | 341 |
| Apr 2026 | 342 |
| May 2026 | 506 |
| Jun 2026 | 549 |
| Jul 2026 | 617 |
Airlines flying BOS–SEA nonstop
| Airline | Flights / week | Share of passengers |
|---|---|---|
| ASAlaska Airlines | 46 | 48% |
| DLDelta Air Lines | 39 | 42% |
| B6JetBlue Airways | 9.3 | 10% |
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
- Airbus Industrie A321-200n · 2,022 flights
- Boeing B737 Max 900 · 1,124 flights
- Boeing 737-900ER · 1,105 flights
- Airbus Industrie A321Neoxlr · 384 flights
- Boeing 737-800 · 144 flights
- Airbus Industrie A320-100/200 · 100 flights
- Boeing B737 Max 800 · 45 flights
Also carried: 1,478 tonnes of freight and 78 tonnes of mail a year (passenger and cargo flights).
Punctuality
- On time
- 73.7%
- Arrived within 15 min of schedule
- Average delay
- 16 min
- Late arrivals count, early ones as 0
- Cancelled
- 1.3%
- Flights counted
- 5,006
- Aug 2025 – Jul 2026
| Airline | On time | Average delay |
|---|---|---|
| ASAlaska Airlines | 73% | 15 min |
| DLDelta Air Lines | 76.5% | 16 min |
| B6JetBlue Airways | 66% | 29 min |
Delay minutes by cause: airline 28% · aircraft arriving late 30% · air traffic system 37% · weather 4% · security 0%.
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
- $323
- One way, all cabins
- Average over a year
- $313
- Q2 2025 – Q1 2026
- Largest airline
- Delta Air Lines
- 48% of passengers · $336
- Lowest-fare airline
- Alaska Airlines
- 46% of passengers · $308
History, not a price to book: what the average passenger paid per one-way trip in each quarter (Q2 2025 $294 · Q3 2025 $311 · Q4 2025 $335 · Q1 2026 $323).
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: 4,006 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 Boston and Seattle
Kilometres. Linked numbers have a page of their own. All Seattle airports
More routes from BOS
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 |