American Airlines flights from Ontario to Saint Louis

Recent searches for flights from Ontario to Saint Louis

Aug 2026
From$372*
Updated: 4 hours ago
Round tripIEconomy
Sep 2026
From$373*
Updated: 15 hours ago
Round tripIEconomy
Oct 2026
From$391*
Updated: 4 hours ago
Round tripIEconomy
cmp-daily-histogram-bars-legend-min-price-aria-label $372
cmp-daily-histogram-bars-legend-max-price-aria-label $743
Displaying fares for August-2026
  • ONT–STL, 08/05/26 – 08/12/26: From $567
    05

    We

    AUG

  • ONT–STL, 08/06/26 – 08/13/26: From $743
    06

    Th

  • ONT–STL, 08/07/26 – 08/14/26: From $743
    07

    Fr

  • ONT–STL, 08/08/26 – 08/22/26: From $522
    08

    Sa

  • ONT–STL, 08/09/26 – 08/16/26: From $743
    09

    Su

  • ONT–STL, 08/10/26 – 08/17/26: From $743
    10

    Mo

  • ONT–STL, 08/11/26 – 08/18/26: From $567
    11

    Tu

  • ONT–STL, 08/12/26 – 08/19/26: From $522
    12

    We

  • ONT–STL, 08/13/26 – 08/20/26: From $675
    13

    Th

  • ONT–STL, 08/14/26 – 08/21/26: From $675
    14

    Fr

  • ONT–STL, 08/15/26 – 08/22/26: From $522
    15

    Sa

  • ONT–STL, 08/16/26 – 08/23/26: From $675
    16

    Su

  • ONT–STL, 08/17/26 – 08/24/26: From $621
    17

    Mo

  • ONT–STL, 08/18/26 – 08/25/26: From $472
    18

    Tu

  • ONT–STL, 08/19/26 – 08/26/26: From $377
    19

    We

  • ONT–STL, 08/20/26 – 08/27/26: From $445
    20

    Th

  • ONT–STL, 08/21/26 – 08/28/26: From $469
    21

    Fr

  • ONT–STL, 08/22/26 – 08/29/26: From $377
    22

    Sa

  • ONT–STL, 08/23/26 – 08/30/26: From $499
    23

    Su

  • ONT–STL, 08/24/26 – 08/31/26: From $445
    24

    Mo

  • ONT–STL, 08/25/26 – 09/01/26: From $377
    25

    Tu

  • ONT–STL, 08/26/26 – 09/02/26: From $377
    26

    We

  • ONT–STL, 08/27/26 – 09/03/26: From $391
    27

    Th

  • ONT–STL, 08/28/26 – 09/04/26: From $439
    28

    Fr

  • ONT–STL, 08/29/26 – 09/05/26: From $372
    29

    Sa

  • ONT–STL, 08/30/26 – 09/06/26: From $433
    30

    Su

  • ONT–STL, 08/31/26 – 09/07/26: From $391
    31

    Mo

  • ONT–STL, 09/01/26 – 09/08/26: From $384
    01

    Tu

    SEP

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

    We

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

    Th

  • ONT–STL, 09/04/26 – 09/11/26: From $403
    04

    Fr

    • range$372-$743

    DisclaimerFares displayed have been collected within the last 24hrs and may no longer be available at time of booking. Modifying this information may result in a different fare. To find the most updated fare, please visit aa.com. Fares listed may be Basic Economy, which class is subject to additional terms and conditions. Additional baggage fees and charges for optional products and services may apply.

    Find deals on Ontario to Saint Louis flights

    $
    keyboard_arrow_down

    Ontario (ONT)to

    Saint Louis (STL)
    08/29/26 - 09/05/26

    Round trip

    Economy

    from
    $372Fare subject to changes
    Updated: 4 hours ago

    Ontario (ONT)to

    Saint Louis (STL)
    09/05/26 - 09/16/26

    Round trip

    Economy

    from
    $373Fare subject to changes
    Updated: 15 hours ago

    Ontario (ONT)to

    Saint Louis (STL)
    08/26/26 - 09/02/26

    Round trip

    Economy

    from
    $377Fare subject to changes
    Updated: 4 hours ago

    Ontario (ONT)to

    Saint Louis (STL)
    08/22/26 - 08/29/26

    Round trip

    Economy

    from
    $377Fare subject to changes
    Updated: 4 hours ago

    Ontario (ONT)to

    Saint Louis (STL)
    08/19/26 - 08/26/26

    Round trip

    Economy

    from
    $377Fare subject to changes
    Updated: 4 hours ago

    Ontario (ONT)to

    Saint Louis (STL)
    08/25/26 - 09/01/26

    Round trip

    Economy

    from
    $377Fare subject to changes
    Updated: 4 hours ago

    Ontario (ONT)to

    Saint Louis (STL)
    09/05/26 - 09/12/26

    Round trip

    Economy

    from
    $379Fare subject to changes
    Updated: 4 hours ago

    Ontario (ONT)to

    Saint Louis (STL)
    09/01/26 - 09/08/26

    Round trip

    Economy

    from
    $384Fare subject to changes
    Updated: 4 hours ago

    *Fares displayed have been collected within the last 24hrs and may no longer be available at time of booking. Some fares listed may include one or more connections that are Basic Economy, which class is subject to additional terms and conditions. Modifying this information may result in a different fare. To find the most updated fare, please visit aa.com. Additional baggage fees and charges for optional products and services may apply.

    Finding cheap flights from Ontario to Saint Louis

    Looking for lower fares on your trip from Ontario to Saint Louis? Here are a few ways to save.

    • Book early: Booking 1 to 3 months ahead can help you find lower fares
    • Be flexible with dates: Midweek travel, like Tuesdays and Wednesdays, can be more affordable
    • Travel during less busy periods: Flying outside peak travel times can help find lower fares and avoid crowds

    Earn up to $500 back on your next American Airlines flight plus, 30,000 bonus miles. Offers vary elsewhere. Opens another site in a new window that may not meet accessibility guidelines.

    Upgrade your flight with Main Cabin Extra

    Make your trip more comfortable with Main Cabin Extra. Enjoy benefits like:

    • Extra legroom: More space with seats at the front of the Main Cabin or in exit rows.
    • Early boarding: Preferred Group 5 boarding allows easier access to overhead bins.
    • Complimentary drinks: Enjoy beer, wine and spirits on flights with full beverage service.

    Discover how Main Cabin Extra can enhance your trip.

    American Airlines flights from Ontario to Saint Louis