Southwest® flights from St. Louis to Ontario/LA from $135

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Low fares from St. Louis to Ontario/LA

$

St. Louis (STL)to

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

One-way

Basic

From
$135
Seen: 10 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 01/23/2027

One-way

Basic

From
$140
Seen: 20 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 01/04/2027

One-way

Basic

From
$140
Seen: 20 hrs ago

St. Louis (STL)to

Ontario/LA (ONT)
Depart: 01/13/2027

One-way

Basic

From
$140
Seen: 8 hrs ago

St. Louis (STL)to

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

One-way

Basic

From
$140
Seen: 1 hour ago

St. Louis (STL)to

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

One-way

Basic

From
$140
Seen: 4 hrs ago

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Explore flights from St. Louis to Ontario/LA

Oct 2026
From$304*
Seen: 18 hrs ago
One Way/Basic
Nov 2026
From$135*
Seen: 11 hrs ago
One Way/Basic
Dec 2026
From$140*
Seen: 21 hrs ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $135
cmp-daily-histogram-bars-legend-max-price-aria-label $392
Displaying fares for October-2026
  • STL–ONT, 10/21/2026: From $304
    21

    Wed

    OCT

  • STL–ONT, 10/22/2026: From $392
    22

    Thu

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

    Fri

  • STL–ONT, 10/24/2026: From $304
    24

    Sat

  • STL–ONT, 10/25/2026: From $392
    25

    Sun

  • STL–ONT, 10/26/2026: From $392
    26

    Mon

  • STL–ONT, 10/27/2026: From $304
    27

    Tue

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

    Wed

  • STL–ONT: cmp-view-offers-disclaimer. Find Offers
    29

    Thu

  • STL–ONT, 10/30/2026: From $392
    30

    Fri

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

    Sat

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

    Sun

    NOV

  • STL–ONT, 11/02/2026: From $392
    02

    Mon

  • STL–ONT, 11/03/2026: From $304
    03

    Tue

  • STL–ONT, 11/04/2026: From $304
    04

    Wed

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

    Thu

  • STL–ONT, 11/06/2026: From $324
    06

    Fri

  • STL–ONT, 11/07/2026: From $299
    07

    Sat

  • STL–ONT, 11/08/2026: From $324
    08

    Sun

  • STL–ONT, 11/09/2026: From $178
    09

    Mon

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

    Tue

  • STL–ONT, 11/11/2026: From $140
    11

    Wed

  • STL–ONT, 11/12/2026: From $284
    12

    Thu

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

    Fri

  • STL–ONT, 11/14/2026: From $135
    14

    Sat

  • STL–ONT, 11/15/2026: From $163
    15

    Sun

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

    Mon

  • STL–ONT: cmp-view-offers-disclaimer. Find Offers
    17

    Tue

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

    Wed

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

    Thu

  • STL–ONT, 11/20/2026: From $208
    20

    Fri

    • Range$135-$392

    *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

    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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