Southwest® flights from Seattle/Tacoma to Ontario/LA from $99

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Low fares from Seattle/Tacoma to Ontario/LA

$

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 12/02/2026

One-way

Basic

From
$99
Seen: 7 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 12/08/2026

One-way

Basic

From
$99
Seen: 3 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 12/09/2026

One-way

Basic

From
$99
Seen: 1 hour ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 02/03/2027

One-way

Basic

From
$125
Seen: 19 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 01/20/2027

One-way

Basic

From
$125
Seen: 11 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 02/20/2027

One-way

Basic

From
$125
Seen: 12 hrs ago

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Explore flights from Seattle/Tacoma to Ontario/LA

Nov 2026
From$269*
Seen: 21 hrs ago
One Way/Basic
Dec 2026
From$99*
Seen: 7 hrs ago
One Way/Basic
Jan 2027
From$125*
Seen: 1 hour ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $99
cmp-daily-histogram-bars-legend-max-price-aria-label $318
Displaying fares for November-2026
  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    12

    Thu

    NOV

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    13

    Fri

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    14

    Sat

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    15

    Sun

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    16

    Mon

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    17

    Tue

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    18

    Wed

  • SEA–ONT, 11/19/2026: From $318
    19

    Thu

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    20

    Fri

  • SEA–ONT, 11/21/2026: From $284
    21

    Sat

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    22

    Sun

  • SEA–ONT, 11/23/2026: From $318
    23

    Mon

  • SEA–ONT, 11/24/2026: From $284
    24

    Tue

  • SEA–ONT, 11/25/2026: From $279
    25

    Wed

  • SEA–ONT, 11/26/2026: From $269
    26

    Thu

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    27

    Fri

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    28

    Sat

  • SEA–ONT, 11/29/2026: From $309
    29

    Sun

  • SEA–ONT, 11/30/2026: From $269
    30

    Mon

  • SEA–ONT, 12/01/2026: From $264
    01

    Tue

    DEC

  • SEA–ONT, 12/02/2026: From $99
    02

    Wed

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    03

    Thu

  • SEA–ONT, 12/04/2026: From $157
    04

    Fri

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    05

    Sat

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    06

    Sun

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    07

    Mon

  • SEA–ONT, 12/08/2026: From $99
    08

    Tue

  • SEA–ONT, 12/09/2026: From $99
    09

    Wed

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    10

    Thu

  • SEA–ONT, 12/11/2026: From $157
    11

    Fri

    • Range$99-$318

    *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

    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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