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Find your next flight from St. Louis to Ontario/LA now!
Looking for low fares? Check out this upcoming flight:
St. Louis, MO to Ontario/LA, CA
*Restrictions and exclusions apply. Seats and dates are limited. Select markets. 24 travel days available. Fares are updated hourly. Fares displayed on external channels may no longer be available at time of booking. To find the most updated fare, please visit Southwest.com.
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Find low faresTravel tips for your next Southwest flight
How to board the plane earlier:
Southwest seats are first come, first served based on check-in order. But there are ways to board the plane earlier!
- Purchase EarlyBird Check-In®1 for automatic check-in and a better boarding position.
Enjoy movies, sips, and snacks during your flight.
Take advantage of inflight entertainment with free movies4, free live TV5, free texting6, and $8 inflight Internet7.
We also offer free sodas, coffee, and snacks8—learn more about the inflight food and beverage experience.
Take advantage of free same-day standby9.
Have a change of travel plans? We offer free same-day standby for all fare types. This means that you can retain your current flight while listing for standby on an earlier flight. If a seat becomes available, it’s yours at no charge!
Make the most of our Rapid Rewards® Program.
Rapid Rewards Members can redeem their points for flights, hotel stays, rental cars, gift cards, and more. And your points never expire!
| Fare | Fly one-way from $209 (departing on 6/30)* |
|---|---|
| Departing from | Lambert-St. Louis International Airport (STL) |
| Arriving at | Ontario International Airport (ONT) |
| Average flight time | Unavailable |
| Distance | 1546 miles |
| 144† | Weekly flights |
|---|---|
| 0 | Nonstop flight per day Monday through Friday |
| 0 | Nonstop flight on Saturday |
| 0 | Nonstop flight on Sunday |
Other popular flights from St. Louis:
†Weekly flights based on DOT published scheduled average flights Monday through Sunday between 4/1/2025 and 4/30/2025. Note: route may not operate every day of the week.
Questions we hear the most
There are 144 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 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.
Visit the Southwest Airlines® Help Center for helpful information and answers to frequently asked questions.
1EarlyBird Check-In® pricing starts at $15 one-way, and is subject to availability. Pricing may vary based on the popularity and length of each (one-way) flight. Please see optional travel charges for more details.
2Upgraded boarding prices and benefits are per eligible segment. Flights must be within 24 hours of departure to be eligible for upgraded boarding.
4Where available. Available only on WiFi-enabled aircraft. Limited-time offer.
5Due to licensing restrictions, on WiFi-enabled international flights, free live TV and iHeartRadio may not be available for the full duration of flight.
6Texting only allows access to iMessage and WhatsApp (which must be downloaded and activated before connecting to SouthwestWiFi).
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.
8Flights traveling 175 miles or less will have only water available. Complimentary snacks are served on flights over 175 miles. If you’re flying between Hawaii and the continental U.S., you’ll have even more snacks to choose from.
9Free same-day standby: You can list for same-day standby for an earlier flight via a Southwest Customer Service Agent at the airport or the Southwest app or mobile web. You must request to be added to the same-day standby list at least 10 minutes prior to the scheduled departure of your original flight or the no-show policy will apply. If using the app or mobile web, you must list your name 30 minutes ahead of scheduled departure. You will receive a message based on the contact preference selected during booking if you are cleared on the flight. Group bookings and Unaccompanied Minors are not eligible for same-day standby. You will be required to pay any government taxes and fees associated with these itinerary changes but refunds will be provided. Your original boarding position is not guaranteed on your standby flight. Southwest Business Customers booked through travel agencies may need to see a Southwest agent at the airport for a standby listing. See Southwest.com/standby for more details.