Southwest® flights from Seattle/Tacoma to Ontario/LA from $119

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Low fares from Seattle/Tacoma to Ontario/LA

$

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 08/27/2026

One-way

Basic

From
$119
Seen: 15 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 08/26/2026

One-way

Basic

From
$124
Seen: 20 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 10/21/2026

One-way

Basic

From
$129
Seen: 10 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 09/03/2026

One-way

Basic

From
$139
Seen: 16 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 10/26/2026

One-way

Basic

From
$139
Seen: 10 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 09/28/2026

One-way

Basic

From
$139
Seen: 10 hrs ago

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Explore flights from Seattle/Tacoma to Ontario/LA

Aug 2026
From$119*
Seen: 15 hrs ago
One Way/Basic
Sep 2026
From$139*
Seen: 10 hrs ago
One Way/Basic
Oct 2026
From$129*
Seen: 10 hrs ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $119
cmp-daily-histogram-bars-legend-max-price-aria-label $414
Displaying fares for August-2026
  • SEA–ONT, 08/02/2026: From $409
    02

    Sun

    AUG

  • SEA–ONT, 08/03/2026: From $414
    03

    Mon

  • SEA–ONT, 08/04/2026: From $414
    04

    Tue

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    05

    Wed

  • SEA–ONT, 08/06/2026: From $414
    06

    Thu

  • SEA–ONT, 08/07/2026: From $319
    07

    Fri

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    08

    Sat

  • SEA–ONT, 08/09/2026: From $324
    09

    Sun

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    10

    Mon

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    11

    Tue

  • SEA–ONT, 08/12/2026: From $324
    12

    Wed

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    13

    Thu

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    14

    Fri

  • SEA–ONT, 08/15/2026: From $189
    15

    Sat

  • SEA–ONT, 08/16/2026: From $194
    16

    Sun

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    17

    Mon

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    18

    Tue

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    19

    Wed

  • SEA–ONT, 08/20/2026: From $194
    20

    Thu

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    21

    Fri

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    22

    Sat

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    23

    Sun

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    24

    Mon

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    25

    Tue

  • SEA–ONT, 08/26/2026: From $124
    26

    Wed

  • SEA–ONT, 08/27/2026: From $119
    27

    Thu

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    28

    Fri

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    29

    Sat

  • SEA–ONT, 08/30/2026: From $189
    30

    Sun

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    31

    Mon

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    01

    Tue

    SEP

    • Range$119-$414

    *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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