Ontario (ONT) to Seattle (SEA)

957mi
1,540 km832 nm

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.

Route map: ONT → SEAONTSEA

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What actually flies ONT–SEA

Filed traffic data

In May 2026, SkyWest Airlines operated the most departures, one of 3 carriers flying nonstop ONT–SEA; the Embraer E175 was the most common aircraft at 50% of departures; flights ran 75% full.

Departures

496

May 2026

Seats

61,707

both directions

Passengers

46,581

both directions

Load factor

75.5%

RPM ÷ ASM

Who flies ONT–SEA?

SkyWest Airlines operated the most nonstop ONT–SEA departures in May 2026 (248), one of 3 carriers on the route.

  • OO

    SkyWest Airlines

    248 departures · 18,368 seats

    79.2%

    Load

  • AS

    Alaska Airlines

    230 departures · 39,201 seats

    75.5%

    Load

  • F9

    Frontier Airlines

    18 departures · 4,138 seats

    58.4%

    Load

What plane flies ONT–SEA?

In May 2026, the Embraer E175 flew 50% of ONT–SEA departures — more than any other aircraft type.

How has ONT–SEA traffic changed?

Nonstop ONT–SEA departures fell from 530 in June 2025 to 496 in May 2026.

Monthly nonstop ONT–SEA traffic, trailing 12 months through May 2026. Bars scale to the busiest month; months with no filed service show as zero.

  • 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

  • May 2026

    496 departures · 46,581 passengers

    75.5%

    Load

By direction

Each direction is filed separately — they rarely match.

SEA → ONT

73.1% full

249 departures · 22,691 passengers

ONT → SEA

77.9% full

247 departures · 23,890 passengers

Nonstop ONT–SEA traffic has been filed since 2025.

Source: US DOT BTS Form 41 T-100 Segment (All Carriers). Data through May 2026; filings from 2025. Public domain (US Government work).

The airports

ONT

Ontario

US

Ontario International Airport

Coordinates

34.06°N, 117.60°W

Hemisphere

N · W

SEA

Seattle

US

Seattle–Tacoma International Airport

Coordinates

47.45°N, 122.31°W

Hemisphere

N · W

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 May 2026, the Embraer E175 flew the largest share of departures (50.0%), followed by the Boeing 737 MAX 9 (18.6%).

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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