$139 Cheap United flights Seattle (SEA) to Ontario (ONT)

View $139 flight on Tue, Jun 9, 2026Opens in a new window

$139 Cheap United flights Seattle (SEA) to Ontario (ONT)

Prices were available within the past 7 days and start at $139 for one-way flights and $197 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Wed, Apr 22 - Sun, Apr 26
SEA
Seattle
ONT
Ontario
$197 Roundtrip, found 2 days ago
$197
Roundtrip
found 2 days ago
Select United flight, departing Wed, Apr 22 from Seattle to Ontario, returning Sun, Apr 26, priced at $197 found 2 days ago
United
Wed, Apr 22 - Sun, Apr 26
SEA
Seattle
ONT
Ontario
$210 Roundtrip, found 2 days ago
$210
Roundtrip
found 2 days ago
Select United flight, departing Wed, Apr 22 from Seattle to Ontario, returning Sun, Apr 26, priced at $210 found 2 days ago
United
Wed, Apr 22 - Sun, Apr 26
SEA
Seattle
ONT
Ontario
$214 Roundtrip, found 2 days ago
$214
Roundtrip
found 2 days ago
Select United flight, departing Wed, Apr 22 from Seattle to Ontario, returning Sun, Apr 26, priced at $214 found 2 days ago

Alternative airports near Ontario

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to John Wayne SNA. Average driving time to city center is 42 minutes. Flights from $327
SNA
John Wayne
Average driving time to city center42 min
Flights from $327

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

October is typically the cheapest month to fly

From $79 - $159 per traveler.

Travel information

Origin airport
Seattle - Tacoma Intl.
Destination airport
Los Angeles - Ontario Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, United
Popular airline
Frontier Airlines
Distance
1530 km
Average flight time
2 hours 53 mins

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