Southwest® flights from St. Louis to Ontario/LA from $179

Promo Code

Low fares from St. Louis to Ontario/LA

$

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 12/16/2026

One-way

Basic

From
$179
Seen: 14 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 12/07/2026

One-way

Basic

From
$179
Seen: 9 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 12/14/2026

One-way

Basic

From
$179
Seen: 20 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 12/24/2026

One-way

Basic

From
$179
Seen: 16 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 11/03/2026

One-way

Basic

From
$179
Seen: 3 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 11/19/2026

One-way

Basic

From
$179
Seen: 3 hrs ago

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Explore flights from St. Louis to Ontario/LA

Oct 2026
From$206*
Seen: 12 hrs ago
One Way/Basic
Nov 2026
From$179*
Seen: 3 hrs ago
One Way/Basic
Dec 2026
From$179*
Seen: 6 hrs ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $206
cmp-daily-histogram-bars-legend-max-price-aria-label $428
Displaying fares for October-2026
  • STL–ONT, 10/02/2026: From $382
    02

    Fri

    OCT

  • STL–ONT, 10/03/2026: From $294
    03

    Sat

  • STL–ONT: cmp-view-offers-disclaimer. Find Offers
    04

    Sun

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    05

    Mon

  • STL–ONT, 10/06/2026: From $294
    06

    Tue

  • STL–ONT, 10/07/2026: From $294
    07

    Wed

  • STL–ONT, 10/08/2026: From $382
    08

    Thu

  • STL–ONT: cmp-view-offers-disclaimer. Find Offers
    09

    Fri

  • STL–ONT, 10/10/2026: From $273
    10

    Sat

  • STL–ONT, 10/11/2026: From $428
    11

    Sun

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

    Mon

  • STL–ONT: cmp-view-offers-disclaimer. Find Offers
    13

    Tue

  • STL–ONT, 10/14/2026: From $294
    14

    Wed

  • STL–ONT, 10/15/2026: From $314
    15

    Thu

  • STL–ONT, 10/16/2026: From $314
    16

    Fri

  • STL–ONT, 10/17/2026: From $294
    17

    Sat

  • STL–ONT, 10/18/2026: From $314
    18

    Sun

  • STL–ONT, 10/19/2026: From $314
    19

    Mon

  • STL–ONT, 10/20/2026: From $294
    20

    Tue

  • STL–ONT, 10/21/2026: From $266
    21

    Wed

  • STL–ONT, 10/22/2026: From $230
    22

    Thu

  • STL–ONT, 10/23/2026: From $216
    23

    Fri

  • STL–ONT: cmp-view-offers-disclaimer. Find Offers
    24

    Sat

  • STL–ONT, 10/25/2026: From $274
    25

    Sun

  • STL–ONT, 10/26/2026: From $216
    26

    Mon

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

    Tue

  • STL–ONT, 10/28/2026: From $206
    28

    Wed

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    29

    Thu

  • STL–ONT, 10/30/2026: From $216
    30

    Fri

  • STL–ONT: cmp-view-offers-disclaimer. Find Offers
    31

    Sat

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

    Sun

    NOV

    • Range$206-$428

    *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:
    Lambert-St Louis Int'l Airport
    Arriving at:
    LA/Ontario International Airport
    Distance:
    1546 miles

    Route Information

    155† 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 155 weekly flights from St. Louis to Ontario/LA on Southwest Airlines.
    To find the lowest fares by day and time to fly St. Louis 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 St. Louis 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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