Cheap flights from Ontario to Seattle

One-way fares from $106 · ONT → SEA · prices found by travellers in the last 48 hours

Compare all dates Seattle → Ontario
Cheapest fare
$106

Frontier Airlines · Tue, Nov 17

Cheapest month
November

from $106

Direct flights
Yes

Alaska Airlines, Southwest Airlines and Frontier Airlines

Flight time
2h 52m

1,560 km

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Cheapest month to fly from Ontario to Seattle

Lowest one-way fare per person in each month. Choose a month to see every date.

  1. November 2026 Cheapest $106
  2. December 2026 $140
  3. January 2027 $178

Cheapest dates in November 2026

The lowest fares we've seen for each day, cheapest first.

Frontier Airlines
Depart11:52 Tue, Nov 17ONT → SEA 5h 29m · 1 stop
$106one way, per person
View deal
Frontier Airlines
Depart06:30 Sat, Nov 7ONT → SEA 5h 29m · 1 stop
$136one way, per person
View deal
Southwest Airlines
Depart20:45 Fri, Nov 6ONT → SEA 4h 35m · Direct
$138one way, per person
View deal
Frontier Airlines
Depart06:30 Fri, Nov 13ONT → SEA 5h 29m · 1 stop
$176one way, per person
View deal
Frontier Airlines
Depart17:06 Sun, Nov 8ONT → SEA 3h 02m · Direct
$180one way, per person
View deal
Frontier Airlines
Depart11:52 Thu, Nov 12ONT → SEA 5h 29m · 1 stop
$180one way, per person
View deal
See every date in November 2026 →

Plan the rest of your trip to Seattle

Where to stay, what to do and getting around, from our travel partners.

Where to stay

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Things to do

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Getting around

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About flights from Ontario to Seattle

Ontario (ONT) and Seattle (SEA) are about 1,560 km apart. Direct flights take around 2h 52m, and recent direct fares were with Alaska Airlines, Southwest Airlines and Frontier Airlines. Over the next few months, one-way fares start from $106, and November 2026 is currently the cheapest month to fly.

These prices come from searches travellers made in the last 48 hours, so they move quickly. If you see a good fare, it's worth booking soon. FlightsExp is free to use: you book directly with our travel partner.

Frequently asked questions

How much is a flight from Ontario to Seattle?

The cheapest one-way fare we've seen recently is $106 with Frontier Airlines, departing Tuesday, November 17, 2026. Over the coming months, the lowest fare in each month ranges from $106 to $178.

What is the cheapest month to fly from Ontario to Seattle?

November 2026 currently has the lowest fares, from $106 one way.

Are there direct flights from Ontario to Seattle?

Yes. Recent direct fares were with Alaska Airlines, Southwest Airlines and Frontier Airlines.

How long is the flight from Ontario to Seattle?

A direct flight takes about 2h 52m. Ontario and Seattle are around 1,560 km apart.

Which airlines fly from Ontario to Seattle?

Recent fares on this route were with Frontier Airlines, Alaska Airlines and Southwest Airlines.

More cheap flights from Ontario

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