An Alaska Airlines plane taking off with a snow-capped mountain in the background.

Flights from Ontario Intl. Airport (ONT) to Seattle-Tacoma International Airport (SEA)
Flights to Seattle
Washington
United States of America
Flights
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Popular airlines from Ontario Intl. Airport (ONT) to Seattle-Tacoma International Airport (SEA)

Alaska Airlines
Frontier Airlines
Delta
United
Southwest Airlines
American Airlines

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Cheap Flights from Ontario to Seattle (ONT-SEA)

Prices were available within the past 7 days and start at NT$4,642 for one-way flights and NT$10,267 for roundtrip, for the period specified. Prices and availability are subject to change.

All deals

One way

Roundtrip

Thu, Sep 24 - Fri, Sep 25

ONT

Ontario

SEA

Seattle

NT$10,267

Roundtrip

Found 5 days ago

Select Delta flight, departing Thu, Sep 24 from Ontario to Seattle, returning Fri, Sep 25, priced at NT$10,267 Found 5 days ago

Thu, Sep 24 - Fri, Sep 25

ONT

Ontario

SEA

Seattle

NT$10,585

Roundtrip

Found 5 days ago

Select Delta flight, departing Thu, Sep 24 from Ontario to Seattle, returning Fri, Sep 25, priced at NT$10,585 Found 5 days ago

Thu, Sep 24 - Fri, Sep 25

ONT

Ontario

SEA

Seattle

NT$10,910

Roundtrip

Found 5 days ago

Select Delta flight, departing Thu, Sep 24 from Ontario to Seattle, returning Fri, Sep 25, priced at NT$10,910 Found 5 days ago

Tue, Jun 8 - Thu, Jun 17

ONT

Ontario

SEA

Seattle

NT$11,583

Roundtrip

Found 3 days ago

Select Delta flight, departing Tue, Jun 8 from Ontario to Seattle, returning Thu, Jun 17, priced at NT$11,583 Found 3 days ago

Thu, Sep 24 - Fri, Sep 25

ONT

Ontario

SEA

Seattle

NT$11,736

Roundtrip

Found 5 days ago

Select Delta flight, departing Thu, Sep 24 from Ontario to Seattle, returning Fri, Sep 25, priced at NT$11,736 Found 5 days ago

Thu, Sep 24 - Fri, Sep 25

ONT

Ontario

SEA

Seattle

NT$11,882

Roundtrip

Found 5 days ago

Select United flight, departing Thu, Sep 24 from Ontario to Seattle, returning Fri, Sep 25, priced at NT$11,882 Found 5 days ago

Tue, Jun 8 - Thu, Jun 17

ONT

Ontario

SEA

Seattle

NT$11,901

Roundtrip

Found 3 days ago

Select Delta flight, departing Tue, Jun 8 from Ontario to Seattle, returning Thu, Jun 17, priced at NT$11,901 Found 3 days ago

Thu, Aug 13 - Mon, Aug 17

ONT

Ontario

SEA

Seattle

NT$12,191

Roundtrip

Found 6 days ago

Select Delta flight, departing Thu, Aug 13 from Ontario to Seattle, returning Mon, Aug 17, priced at NT$12,191 Found 6 days ago

Fri, Sep 4 - Mon, Sep 7

ONT

Ontario

SEA

Seattle

NT$12,702

Roundtrip

Found 4 days ago

Select Alaska Airlines flight, departing Fri, Sep 4 from Ontario to Seattle, returning Mon, Sep 7, priced at NT$12,702 Found 4 days ago

Sun, Jun 13 - Sun, Jun 20

ONT

Ontario

SEA

Seattle

NT$15,796

Roundtrip

Found 1 day ago

Select American Airlines flight, departing Sun, Jun 13 from Ontario to Seattle, returning Sun, Jun 20, priced at NT$15,796 Found 1 day ago

Find the cheapest month to fly from Ontario (ONT) to Seattle (SEA)

August is typically the cheapest month to fly

From NT$2,842 - NT$7,723 per traveler.

Travel information

Origin airport	Ontario Intl. Airport
Destination airport	Seattle-Tacoma International Airport
Distance	1,539 km away
Airlines serving	Alaska Airlines, Frontier Airlines, Delta, United, Southwest Airlines, American Airlines
Popular airline	Alaska Airlines
Roundtrip price	NT$10,267
Average flight time	2 hours 46 mins

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NT$4,642 Cheap Flights from Ontario Intl. Airport (ONT) to Seattle (SEA)

Popular airlines from Ontario Intl. Airport (ONT) to Seattle-Tacoma International Airport (SEA)

Be in the know

Book smarter

Earn twice

Cheap Flights from Ontario to Seattle (ONT-SEA)

Find the cheapest month to fly from Ontario (ONT) to Seattle (SEA)

August is typically the cheapest month to flyAugust is typically the cheapest month to fly

Travel information

Explore a world of travel with Expedia

August is typically the cheapest month to fly