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Southwest® flights from Seattle/Tacoma to Ontario/LA from $109

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Low fares from Seattle/Tacoma to Ontario/LA

$

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 06/06/2026

One-way

Basic

From
$109
Seen: 21 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 06/05/2026

One-way

Basic

From
$124
Seen: 5 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 06/03/2026

One-way

Basic

From
$149
Seen: 8 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 06/06/2026

One-way

Choice

From
$149
Seen: 21 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 06/08/2026

One-way

Basic

From
$149
Seen: 4 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 06/04/2026

One-way

Basic

From
$149
Seen: 17 hrs ago

Looking for more low-fare flights?

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Explore flights from Seattle/Tacoma to Ontario/LA

May 2026
From$229*
Seen: 23 hrs ago
One Way/Basic
Jun 2026
From$109*
Seen: 21 hrs ago
One Way/Basic
Jul 2026
From$174*
Seen: 9 hrs ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $109
cmp-daily-histogram-bars-legend-max-price-aria-label $384
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    • Range$109-$384

    *Fares displayed have been collected within the last 24 hours and may no longer be available at time of booking. Additional fees and charges for optional products and services may apply. Modifying this information may result in a different fare. To find the most updated fare, please visit Southwest.com. Fares listed are Basic, which are subject to additional terms and conditions.

    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.

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