Southwest® flights from Seattle/Tacoma to Ontario/LA from $134

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Low fares from Seattle/Tacoma to Ontario/LA

$

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 11/14/2026

One-way

Basic

From
$134
Seen: 14 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 10/24/2026

One-way

Basic

From
$134
Seen: 4 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 11/11/2026

One-way

Basic

From
$134
Seen: 15 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 10/05/2026

One-way

Basic

From
$149
Seen: 14 hrs ago

Seattle/Tacoma (SEA)to

Ontario/LA (ONT)
Depart: 10/02/2026

One-way

Basic

From
$149
Seen: 16 hrs ago

Seattle/Tacoma (SEA)to

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

One-way

Basic

From
$149
Seen: 17 hrs ago

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Explore flights from Seattle/Tacoma to Ontario/LA

Aug 2026
From$257*
Seen: 23 hrs ago
One Way/Basic
Sep 2026
From$149*
Seen: 17 hrs ago
One Way/Basic
Oct 2026
From$134*
Seen: 4 hrs ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $149
cmp-daily-histogram-bars-legend-max-price-aria-label $303
Displaying fares for August-2026
  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    22

    Sat

    AUG

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    23

    Sun

  • SEA–ONT, 08/24/2026: From $298
    24

    Mon

  • SEA–ONT, 08/25/2026: From $262
    25

    Tue

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    26

    Wed

  • SEA–ONT, 08/27/2026: From $298
    27

    Thu

  • SEA–ONT, 08/28/2026: From $298
    28

    Fri

  • SEA–ONT, 08/29/2026: From $257
    29

    Sat

  • SEA–ONT, 08/30/2026: From $303
    30

    Sun

  • SEA–ONT, 08/31/2026: From $298
    31

    Mon

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    01

    Tue

    SEP

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    02

    Wed

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

    Thu

  • SEA–ONT, 09/04/2026: From $244
    04

    Fri

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

    Sat

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

    Sun

  • SEA–ONT, 09/07/2026: From $244
    07

    Mon

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    08

    Tue

  • SEA–ONT, 09/09/2026: From $244
    09

    Wed

  • SEA–ONT, 09/10/2026: From $239
    10

    Thu

  • SEA–ONT, 09/11/2026: From $184
    11

    Fri

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    12

    Sat

  • SEA–ONT, 09/13/2026: From $189
    13

    Sun

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    14

    Mon

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    15

    Tue

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    16

    Wed

  • SEA–ONT, 09/17/2026: From $174
    17

    Thu

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    18

    Fri

  • SEA–ONT: cmp-view-offers-disclaimer. Find Offers
    19

    Sat

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    20

    Sun

  • SEA–ONT, 09/21/2026: From $149
    21

    Mon

    • Range$149-$303

    *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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