Visit Gateway City and discover what St. Louis has to offer.
Book flights from Ontario/LA to St. Louis with Southwest Airlines®. It’s easy to find the Ontario International Airport to Lambert-St. Louis International Airport flight to make your booking and travel a breeze. Whether you’re traveling for business or pleasure, solo or with the whole family, you’ll enjoy flying Southwest®. Have flexible travel dates? Plug them into the Low Fare Calendar and see the lowest fares available within your travel window. You may also want to browse Southwest Vacations® to see special offers and package deals on flights, hotels, rental cars, and more.
Explore your options and book your Ontario/LA to St. Louis flight with Southwest today!
Ontario/LA, CA to St. Louis, MO
departing on 7/12
one-way starting at*$243
*Restrictions and exclusions apply. Seats and dates are limited. Select markets. 43 travel days available.
|Departing from||Ontario International Airport (ONT)|
|Arriving at||Lambert-St. Louis International Airport (STL)|
Other popular flights from Ontario/LA:View our interactive map
†Weekly flights based on DOT published scheduled average flights Monday through Sunday between 6/1/2023 and 6/30/2023. Note: route may not operate every day of the week.
One child over 14 days and under two (2) years of age, not occupying a seat, may be carried free of charge when traveling with an adult (12 years of age or older). Learn more.
Customers flying with a pet are subject to a pet fare. To learn more about traveling with your furry friend, explore the Southwest® pet policy.
Minors under the age of 18 are not permitted to fly unaccompanied on international flights or any itinerary that includes an international flight. Learn more.
Lambert-St. Louis International Airport will bring you within 14 miles of downtown St. Louis. Hop on a bus, or train, or call a car to get on your way.
At Southwest, we know it takes more than great deals on St. Louis airfares and convenient scheduling options to make your trip memorable. So from booking to boarding, we offer services and features designed to make your travel from Ontario/LA to St. Louis the best it can be. Learn more about the Southwest® travel experience before you book your flight from Ontario International Airport to Lambert-St. Louis International Airport.
Flying with Southwest is simple and fun, no matter which of our dozens of exciting destinations you choose. When you search for your next flight to St. Louis, know that you won’t be surprised at checkout. Low fares and no hidden fees. That's Transfarency®. And as always, two bags fly free®1. Want the latest news, information, and promotional offers from Southwest? Sign up to receive email from us. Book your flight today and know that you'll earn Rapid Rewards® points when you fly.
1First and second checked bags. Weight and size limits apply.
2Fare difference may apply.
3Failure to cancel a reservation at least 10 minutes prior to departure may result in forfeited Travel Funds.
4Flight credits unexpired on or created on or after July 28, 2022, do not expire and will show an expiration date until our systems are updated. See full details here.
5Where available. Available only on WiFi-enabled aircraft. Limited-time offer.
6Due to licensing restrictions, on WiFi-enabled international flights, free live TV and iHeartRadio may not be available for the full duration of flight.
7Internet access for $8 per device from takeoff to landing. Price is subject to change. May not be available for the full duration of flight. In order to provide a top-notch Internet experience, we prohibit access to certain high-bandwidth applications and websites. We also prohibit access to certain obscene or offensive content.