United flights from Ontario to Saint Louis from $ 339* or from $/mo

Changed bag rules and optional services         Cruise Packages

Featured daily fares for flights from Ontario (ONT) to Saint Louis (STL)

Try alternate month or interact with individual days below in order to find offers.
Mar 2025
No result for this month
Mar 2025
From$ 636*
Viewed: 1 hour ago
RoundTrip|Economy
Mar 2025
From$ 636*
Viewed: 1 hour ago
RoundTrip|Economy
$ 267
$ 848
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Range$ 267-$ 848

*Prices have been available for round trips within the last 48 hours and may not be currently available. For Economy class, fares listed may be Basic Economy, which is our most restrictive fare option and subject to additional restrictions. Additional baggage charges and fees for other optional service may apply. Other terms and conditions may apply.

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