Ontario (ONT) to Seattle (SEA)
Flight time
≈ 2h 43m
Bearing
347° N
Ontario (ONT) to Seattle (SEA) is 957 miles (1,540 km) as the crow flies — the great-circle baseline most distance-based mileage programs credit.
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What actually flies ONT–SEA
US DOT T-100 · filed dataIn April 2026, SkyWest Airlines operated the most departures, one of 2 carriers flying nonstop ONT–SEA; the Embraer E175 was the most common aircraft at 54% of departures; flights ran 78% full.
Departures
400
April 2026
Seats
47,308
both directions
Passengers
37,003
both directions
Load factor
78.2%
passengers ÷ seats
Who flies ONT–SEA?
SkyWest Airlines operated the most nonstop ONT–SEA departures in April 2026 (216), one of 2 carriers on the route.
- OO
SkyWest Airlines
216 departures · 15,822 seats
Share of departures54.0%78.9%
Load
- AS
Alaska Airlines
184 departures · 31,486 seats
Share of departures46.0%77.9%
Load
What plane flies ONT–SEA?
In April 2026, the Embraer E175 flew 54% of ONT–SEA departures — more than any other aircraft type.
- Embraer E175
216 departures · 78.9% load
54.0% - Boeing 737-900ER
80 departures · 76.0% load
20.0% - Boeing 737 MAX 9
67 departures · 80.9% load
16.8% - Boeing 737-700
17 departures · 77.9% load
4.3% - Boeing 737-800
12 departures · 77.6% load
3.0% - Boeing 737 MAX 8
8 departures · 71.3% load
2.0%
How has ONT–SEA traffic changed?
Nonstop ONT–SEA departures fell from 511 in May 2025 to 400 in April 2026.
Monthly nonstop ONT–SEA traffic, trailing 12 months through April 2026. Bars scale to the busiest month; months with no filed service show as zero.
May 2025
511 departures · 52,564 passengers
82.4%
Load
June 2025
530 departures · 59,981 passengers
87.2%
Load
July 2025
589 departures · 69,653 passengers
89.3%
Load
August 2025
530 departures · 65,377 passengers
88.3%
Load
September 2025
428 departures · 48,745 passengers
85.6%
Load
October 2025
398 departures · 41,801 passengers
84.6%
Load
November 2025
413 departures · 45,527 passengers
80.4%
Load
December 2025
398 departures · 45,864 passengers
87.9%
Load
January 2026
320 departures · 34,792 passengers
81.0%
Load
February 2026
271 departures · 30,479 passengers
85.7%
Load
March 2026
348 departures · 36,446 passengers
84.4%
Load
April 2026
400 departures · 37,003 passengers
78.2%
Load
By direction
The DOT files each direction separately — they rarely match.
SEA → ONT
77.2% full
201 departures · 18,382 passengers
ONT → SEA
79.2% full
199 departures · 18,621 passengers
Nonstop ONT–SEA traffic has been filed with the US DOT since 2025.
Source: US DOT BTS Form 41 T-100 Segment (All Carriers). Data through April 2026; filings from 2025. Public domain (US Government work). The DOT publishes roughly three months in arrears.
The airports
Frequently asked
How far is Ontario (ONT) from Seattle (SEA)?
ONT to SEA is 957 miles (1,540 km / 832 nautical miles) measured great-circle — the shortest path over the surface of the Earth.
How long is the flight from ONT to SEA?
A nonstop covers the 957-mile great-circle distance in roughly 2h 43m of block time, before winds. Actual schedules vary a few percent by direction and aircraft.
What plane flies ONT–SEA?
In April 2026, the Embraer E175 flew the largest share of departures (54.0%), followed by the Boeing 737-900ER (20.0%).
What mileage do I earn flying ONT–SEA?
Distance-based programs credit off the 957-mile great-circle figure, then apply your fare-class earning rate. Revenue-based programs credit off the fare instead.
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