Cheap flights from Seattle to Ontario

View AU$136 flight on Wed, 27 Aug. 2025Opens in a new window

Popular airlines from Seattle to Ontario

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Cheap Flights from Seattle (SEA) to Ontario (QLA)

Prices were available within the past 7 days for one-way flights and round trip tickets for the period specified. Prices and availability are subject to change. Additional terms apply.

Hawaiian Airlines
Sat, 16 Aug. - Tue, 19 Aug.
SEA
Seattle
ONT
Ontario
AU$210 Return, found 1 day ago
AU$210
Return
found 1 day ago
Select Hawaiian Airlines flight, departing Sat, 16 Aug. from Seattle to Ontario, returning Tue, 19 Aug., priced at AU$210 found 1 day ago
Hawaiian Airlines
Thu, 14 Aug. - Tue, 19 Aug.
SEA
Seattle
ONT
Ontario
AU$256 Return, found 1 day ago
AU$256
Return
found 1 day ago
Select Hawaiian Airlines flight, departing Thu, 14 Aug. from Seattle to Ontario, returning Tue, 19 Aug., priced at AU$256 found 1 day ago
Delta
Sat, 16 Aug. - Sat, 30 Aug.
SEA
Seattle
ONT
Ontario
AU$270 Return, just found
AU$270
Return
just found
Select Delta flight, departing Sat, 16 Aug. from Seattle to Ontario, returning Sat, 30 Aug., priced at AU$270 just found
Alaska Airlines
Fri, 5 Sep. - Mon, 22 Sep.
SEA
Seattle
ONT
Ontario
AU$299 Return, just found
AU$299
Return
just found
Select Alaska Airlines flight, departing Fri, 5 Sep. from Seattle to Ontario, returning Mon, 22 Sep., priced at AU$299 just found
United
Wed, 24 Sep. - Fri, 26 Sep.
SEA
Seattle
ONT
Ontario
AU$368 Return, found 22 hours ago
AU$368
Return
found 22 hours ago
Select United flight, departing Wed, 24 Sep. from Seattle to Ontario, returning Fri, 26 Sep., priced at AU$368 found 22 hours ago
American Airlines
Wed, 24 Sep. - Fri, 26 Sep.
SEA
Seattle
ONT
Ontario
AU$459 Return, found 22 hours ago
AU$459
Return
found 22 hours ago
Select American Airlines flight, departing Wed, 24 Sep. from Seattle to Ontario, returning Fri, 26 Sep., priced at AU$459 found 22 hours ago

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

October is typically the cheapest month to fly

From AU$100 - AU$286 per traveller.

Graph displaying average flight prices per month

*Available to Expedia members.