Ontario to Seattle (ONT-SEA): nonstop upgrade & award space

Alaska Airlines, Delta Air Lines, and Frontier Airlines fly nonstop between Ontario (ONT) and Seattle (SEA), roughly 60 times a week. The timetable below shows the nonstop scheduled at 2h 43m to 3h 4m for the 957 miles. 2LNR checks confirmed upgrade and award space on Alaska Airlines and Delta Air Lines flights on this route, so you can see which departures have space before you book.

Schedule last confirmed . Departure times come from 2LNR's schedule data; confirm with the airline before you book.

Updated .

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60
Flights a week, 4-week average
2h 43m to 3h 4m
Scheduled flight time
957 mi
Nonstop distance
Free
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Ontario to Seattle flight schedule

Scheduled nonstop departures for ONT to SEA starting October 28, 2026, last checked against our schedule feed on October 25, 2026. Airlines retime and cancel flights, so confirm with the airline before you book.

Schedule data dated .

Scheduled nonstop departures from Ontario (ONT) to Seattle (SEA)
Date Flight Airline Departs ONT Arrives SEA Duration Aircraft
AS 607Alaska Airlines, Inc.06:0208:492h 47mBoeing 737-900
DL 3816Delta Air Lines06:2009:243h 4mEmbraer E175
AS 475Alaska Airlines, Inc.11:1313:562h 43mBoeing 737-800
DL 4070Delta Air Lines11:5614:552h 59mEmbraer E175
AS 575Alaska Airlines, Inc.14:1316:562h 43mBoeing 737-800
F9 2275Frontier Airlines17:0520:012h 56mAirbus A321
DL 4031Delta Air Lines18:0020:592h 59mEmbraer E175
AS 592Alaska Airlines, Inc.18:5621:412h 45mBoeing 737-900
AS 607Alaska Airlines, Inc.06:0208:492h 47mBoeing 737-900
DL 3816Delta Air Lines06:2009:243h 4mEmbraer E175
AS 475Alaska Airlines, Inc.11:1313:562h 43mBoeing 737 MAX 9
DL 4070Delta Air Lines11:5614:552h 59mEmbraer E175
AS 575Alaska Airlines, Inc.14:1316:562h 43mBoeing 737 MAX 9
F9 2275Frontier Airlines17:0620:083h 2mAirbus A320neo
DL 4031Delta Air Lines18:0020:592h 59mEmbraer E175
AS 592Alaska Airlines, Inc.18:5621:392h 43mBoeing 737-900
AS 607Alaska Airlines, Inc.06:0208:492h 47mBoeing 737-900
DL 3816Delta Air Lines06:2009:243h 4mEmbraer E175
AS 475Alaska Airlines, Inc.11:1313:562h 43mBoeing 737 MAX 9
DL 4070Delta Air Lines11:5614:552h 59mEmbraer E175
AS 575Alaska Airlines, Inc.14:1316:562h 43mBoeing 737-900
F9 2275Frontier Airlines17:0620:083h 2mAirbus A320neo
DL 4031Delta Air Lines18:0020:592h 59mEmbraer E175
AS 592Alaska Airlines, Inc.18:5621:392h 43mBoeing 737 MAX 9
AS 607Alaska Airlines, Inc.06:0208:492h 47mBoeing 737-900
DL 3816Delta Air Lines06:2009:243h 4mEmbraer E175
AS 475Alaska Airlines, Inc.11:1313:562h 43mBoeing 737-900
DL 4070Delta Air Lines11:5514:583h 3mEmbraer E175
AS 575Alaska Airlines, Inc.14:1316:562h 43mBoeing 737 MAX 9
F9 2275Frontier Airlines17:0520:012h 56mAirbus A321
DL 4031Delta Air Lines18:0020:592h 59mEmbraer E175
AS 592Alaska Airlines, Inc.18:5621:412h 45mBoeing 737-900
AS 607Alaska Airlines, Inc.06:0008:512h 51mBoeing 737-900
DL 3816Delta Air Lines06:2009:243h 4mEmbraer E175
DL 4070Delta Air Lines11:5614:552h 59mEmbraer E175
AS 575Alaska Airlines, Inc.12:0214:492h 47mBoeing 737-900
AS 571Alaska Airlines, Inc.16:0918:562h 47mBoeing 737-900
F9 2275Frontier Airlines17:2720:293h 2mAirbus A320neo
DL 4031Delta Air Lines18:0020:592h 59mEmbraer E175
AS 594Alaska Airlines, Inc.19:1322:002h 47mBoeing 737 MAX 9

Showing the first 40 of 56 scheduled ONT to SEA departures across 7 days with service, starting October 28, 2026. Every remaining date is on the interactive map.

Departure and arrival times are local at their own airport, so an arrival can fall on a different local date than the departure; the duration column is the true elapsed flying time. A dash means the airline hasn't filed that value in the schedule data we hold. Aircraft are the equipment the airline filed, named where the code pins down one type and shown as the family or the bare code where it doesn't. Swaps can happen up to departure.

See every ONT to SEA date on the interactive map

Aircraft on the Ontario to Seattle nonstop

In the schedule table on this page, Alaska Airlines flies the Boeing 737-900, the Boeing 737 MAX 9, and the Boeing 737-800. Delta Air Lines flies the Embraer E175. Frontier Airlines flies the Airbus A320neo and the Airbus A321. Each linked aircraft page shows where that airline schedules it. Airlines can swap aircraft up to departure.

Confirmed upgrade & award space on ONT to SEA departures

2LNR tracks confirmed upgrade and award space on Alaska Airlines and Delta Air Lines, segment by segment and date by date. Open the calendar for Ontario to Seattle to see which departures have space, the next 14 days free on every product and the full horizon on Pro.

In the 7 days to October 26, 2026, 2LNR checked award space on Ontario to Seattle departures from October 26 to November 8. Alaska Airlines had space open on 13 of 14 dates checked and Delta Air Lines on 14 of 14.

See real availability

Confirmed upgrade or award seats by date on the ONT to SEA departures 2LNR tracks, checked against live inventory so you know what's open before you book.

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Premium inventory turns over fast. Watch this route on Pro and 2LNR notifies you when space appears on a date you're tracking.

Plan on the map

See ONT to SEA on the interactive route map, with schedules, connections, and route statistics.

Airlines flying Ontario to Seattle nonstop

Carriers operating ONT to SEA nonstop in the current schedule. Where 2LNR tracks the carrier, its departures show confirmed upgrade or award space by date.

See ONT to SEA on the interactive map →

Frequently asked questions about ONT to SEA

How long is the flight from Ontario (ONT) to Seattle (SEA)?
Scheduled flight times from Ontario (ONT) to Seattle (SEA) run from 2h 43m to 3h 4m across the departures in the schedule table on this page. The nonstop covers about 957 miles, and airlines adjust scheduled times by season, so confirm with the airline before you book.
Which airlines fly nonstop from ONT to SEA?
Alaska Airlines, Delta Air Lines, and Frontier Airlines fly ONT to SEA nonstop. 2LNR tracks confirmed upgrade and award space on Alaska Airlines and Delta Air Lines.
How many flights a week are there from ONT to SEA?
About 60 nonstop flights a week run between Ontario (ONT) and Seattle (SEA) in the current schedule, operated by Alaska Airlines, Delta Air Lines, and Frontier Airlines. Frequency shifts by season, and the schedule table on this page shows what is scheduled next.
What time do flights from ONT to SEA depart?
Scheduled ONT to SEA nonstops in the next 7 days with service leave between 06:00 and 19:13, local time at Ontario. The schedule table on this page lists every departure by date, with its arrival time and aircraft.
Which flights operate ONT to SEA nonstop?
The schedule table on this page lists 10 flight numbers for ONT to SEA nonstops, including AS 475, AS 575, AS 592, and AS 607 on Alaska Airlines; DL 3816, DL 4031, and DL 4070 on Delta Air Lines; and F9 2275 on Frontier Airlines. The table lists each departure by date with its times and aircraft.
How do I check upgrade or award availability on ONT to SEA?
Open the ONT to SEA route on the interactive map or the matrix to see confirmed upgrade and award space by date on Alaska Airlines and Delta Air Lines, the next 14 days free and the full horizon on Pro. On Pro you can also set an alert on the route and 2LNR notifies you when space opens.

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See what's open by date on this route, the next 14 days free on every product and the full horizon on Pro.

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