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Find low faresSouthwest® flights from Seattle/Tacoma to Ontario/LA from $89
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1 Passenger
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today
Low fares from Seattle/Tacoma to Ontario/LA
$
Seattle/Tacoma (SEA)to
Ontario/LA (ONT)
Depart: 04/01/2026
One-way
Basic
From
$89
Seen: 1 hour ago
Seattle/Tacoma (SEA)to
Ontario/LA (ONT)
Depart: 05/07/2026
One-way
Basic
From
$99
Seen: 3 hrs ago
Seattle/Tacoma (SEA)to
Ontario/LA (ONT)
Depart: 04/13/2026
One-way
Basic
From
$99
Seen: 12 hrs ago
Seattle/Tacoma (SEA)to
Ontario/LA (ONT)
Depart: 02/27/2026
One-way
Basic
From
$99
Seen: 25 minutes ago
Seattle/Tacoma (SEA)to
Ontario/LA (ONT)
Depart: 04/01/2026
One-way
Choice
From
$124
Seen: 1 hour ago
Seattle/Tacoma (SEA)to
Ontario/LA (ONT)
Depart: 04/13/2026
One-way
Choice
From
$134
Seen: 12 hrs ago
Explore flights from Seattle/Tacoma to Ontario/LA
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Flight Details
Departing from:
Seattle/Tacoma International Airport
Arriving at:
LA/Ontario International Airport
Distance:
956 miles
Route Information
135† Weekly flights
† Weekly flights based on DOT published scheduled average flights Monday through Sunday between 9/1/2025 and 9/30/2025. Note: route may not operate every day of the week.
‡ Nonstop flights based on DOT published scheduled average flights Monday through Sunday between 9/1/2025 and 9/30/2025.
Questions we hear the most
There are 135 weekly flights from Seattle/Tacoma to Ontario/LA on Southwest Airlines.
To find the lowest fares by day and time to fly Seattle/Tacoma to Ontario/LA with Southwest, check out our Low Fare Calendar.
You can rent a car at LA/Ontario International Airport book yours with your flight.
Yes! Flights from Seattle/Tacoma to Ontario/LA—or from here or there to anywhere—can be changed with no change fees. Fare difference may apply.
Check the status of your upcoming Southwest flight.
Check out the Southwest Airlines® Help Center for answers about everything Southwest.