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 55 times a week. With Alaska Airlines running most of the schedule, the shape of a week is predictable, which makes an open premium seat on a given date easy to spot and quick to lose. 2LNR tracks confirmed upgrade and award space on Alaska Airlines and Delta Air Lines, on every ONT to SEA departure, so you know which flights have space before you book.

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

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55
Nonstop flights a week
957 mi
Nonstop distance
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Ontario to Seattle flight schedule

Scheduled nonstop departures for ONT to SEA, last checked against our schedule feed on September 6, 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
DL 3816Delta Air Lines06:0009:003hE7W
AS 607Alaska Airlines, Inc.06:0208:452h 43m73H
DL 4070Delta Air Lines11:5414:502h 56mE7W
AS 654Alaska Airlines, Inc.12:1214:552h 43m73H
AS 575Alaska Airlines, Inc.15:1417:562h 42m73J
F9 2275Frontier Airlines17:4420:402h 56m32N
DL 4031Delta Air Lines18:0020:502h 50mE7W
DL 3816Delta Air Lines06:0009:003hE7W
AS 607Alaska Airlines, Inc.06:0208:452h 43m73H
DL 4070Delta Air Lines11:5414:502h 56mE7W
AS 654Alaska Airlines, Inc.12:1214:552h 43m7M9
AS 575Alaska Airlines, Inc.15:1417:562h 42m73J
F9 2275Frontier Airlines17:4420:402h 56m32N
DL 4031Delta Air Lines18:0020:502h 50mE7W
AS 594Alaska Airlines, Inc.19:5922:412h 42m73J
DL 3816Delta Air Lines06:0009:003hE7W
AS 607Alaska Airlines, Inc.06:0208:452h 43m73H
DL 4070Delta Air Lines11:5414:502h 56mE7W
AS 654Alaska Airlines, Inc.12:1214:552h 43m73H
AS 575Alaska Airlines, Inc.15:1417:562h 42m73J
F9 2275Frontier Airlines17:4420:402h 56m32N
DL 4031Delta Air Lines18:0020:502h 50mE7W
AS 594Alaska Airlines, Inc.19:5922:412h 42m7M9
DL 3816Delta Air Lines06:0009:003hE7W
AS 607Alaska Airlines, Inc.06:0208:452h 43m73J
DL 4070Delta Air Lines11:5514:563h 1mE7W
AS 654Alaska Airlines, Inc.12:1214:552h 43m73J
AS 575Alaska Airlines, Inc.15:1417:562h 42m73J
F9 2275Frontier Airlines17:3420:302h 56m32Q
DL 4031Delta Air Lines18:0020:502h 50mE7W
DL 3816Delta Air Lines06:0009:003hE7W
AS 607Alaska Airlines, Inc.06:0208:452h 43m73J
DL 4070Delta Air Lines11:5414:502h 56mE7W
AS 654Alaska Airlines, Inc.12:1214:552h 43m73J
AS 575Alaska Airlines, Inc.15:1417:562h 42m73J
F9 2275Frontier Airlines17:4420:402h 56m32N
DL 4031Delta Air Lines18:0020:502h 50mE7W
AS 594Alaska Airlines, Inc.19:5922:412h 42m73J
DL 3816Delta Air Lines06:0009:003hE7W
AS 607Alaska Airlines, Inc.06:0208:452h 43m7M9

Showing the first 40 of 53 scheduled ONT to SEA departures across the next 7 days with service. 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 has not filed that value in the schedule data we hold. Aircraft are IATA equipment codes as filed, and can change up to departure.

See every ONT to SEA date on the interactive map

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.

See real availability

Confirmed upgrade and award seats on each ONT to SEA departure, checked against live inventory so you know what is open before you book.

Set an alert

Premium inventory turns over fast. Watch this route and 2LNR notifies you when space appears on a date you are 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. 2LNR tracks confirmed upgrade and award space on each of them.

See ONT to SEA on the interactive map →

Frequently asked questions about ONT to SEA

How far is Seattle from Ontario?
ONT to SEA covers about 957 miles nonstop. Flight times vary by aircraft and season; the schedule table on this page lists each scheduled departure with its own times.
Which airlines fly nonstop from ONT to SEA?
Alaska Airlines, Delta Air Lines, and Frontier Airlines fly the route 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 55 nonstop flights a week run between Ontario and Seattle 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 19:59, local time at Ontario. The schedule table on this page lists every departure by date, with its arrival time 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.

Never miss ONT to SEA upgrade or award space

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

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