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Cheap flights from Ontario to St Louis from US$179
There are no direct flights from Ontario to St Louis. The fastest way is one stop via Denver or Phoenix, about 4h 30m door to door (248 connections a week on current schedules), with fares from US$179.
No direct flights · 6 connection options From 4h 25m Cheapest in March Prices checked 13 days ago
Ontario to St Louis at a glance
Cheapest one-wayUS$179Frontier Airlines · 1 stop · Mon 1 MarCheapest returnUS$168Fri 6 Nov – Mon 9 NovFastest journey4h 25mFrontier Airlines · 1 stop
Nonstop flightsNoneConnect via Denver or Phoenix
Best ways to fly from Ontario to St Louis
Ranked by how easy the connection is: one airline or alliance first (bags and connection protected), then the quickest self-transfer options.
1Search
ONT Denver (DEN) STL
Leg 1: Frontier Airlines, Southwest Airlines, United Airlines · Leg 2: Frontier Airlines, Southwest Airlines, United Airlines
Thu08:30 ONT11:25 DEN0h 50m connection12:15 DEN15:00 STLSouthwest Airlines
2Search
ONT Phoenix (PHX) STL
Leg 1: American Airlines, Southwest Airlines · Leg 2: American Airlines, Frontier Airlines, Southwest Airlines
Wed15:45 ONT16:47 PHX0h 58m connection17:45 PHX22:25 STLSouthwest Airlines
3Search
ONT Las Vegas (LAS) STL
Leg 1: Frontier Airlines, Southwest Airlines · Leg 2: Frontier Airlines, Southwest Airlines, Sun Country Airlines
Sat15:00 ONT15:50 LAS1h 10m connection17:00 LAS21:54 STLSouthwest Airlines
4Search
ONT Salt Lake City (SLC) STL
Leg 1: Delta Air Lines · Leg 2: Delta Air Lines, Southwest Airlines
Fri06:00 ONT08:32 SLC0h 58m connection09:30 SLC13:07 STLDelta Air Lines
5Search
ONT Dallas (DFW) STL
Leg 1: American Airlines, Frontier Airlines · Leg 2: American Airlines, Frontier Airlines, Envoy Air
Tue07:15 ONT12:02 DFW0h 58m connection13:00 DFW14:31 STLAmerican Airlines
6Search
ONT San Francisco (SFO) STL
Leg 1: Frontier Airlines, United Airlines · Leg 2: Southwest Airlines, United Airlines
Mon10:45 ONT11:57 SFO0h 48m connection12:45 SFO18:31 STLUnited Airlines
Connections are computed from flights actually flown over the last 8 weeks, with at least 45 minutes to change on one airline and 2 hours on separate tickets. Times are local. The search shows live itineraries and exact times.
Cheapest dates from Ontario to St Louis
The lowest one-way fares found recently, cheapest first. Prices change; click through for the live fare.
Cheapest month to fly from Ontario to St Louis
Lowest one-way fare found for each month: March is cheapest, December the most expensive.
Good to know
- Distance
- 2,500 km1,553 miles
- Journey time
- 4h 25mfastest found
- Time difference
- +2hSt Louis vs Ontario
- Currency in St Louis
- USD
- Airports
- ONT → STL
Flights from Ontario to St Louis: questions answered
How much is a flight from Ontario to St Louis?
The cheapest one-way fare we found recently is US$179 with 1 stop, departing in March. Return trips start from US$168. Prices change constantly, so search your dates for the live fare.
Are there direct flights from Ontario to St Louis?
No. There is no nonstop service, so you will connect, most easily in Denver, Phoenix and Las Vegas. Some connections are on one airline or alliance, so your bags and connection are protected on a single ticket.
How long is the flight from Ontario to St Louis?
With one connection the journey usually takes around 4h 25m, depending on the layover. The straight-line distance is 2,500 km.
Where do you change planes between Ontario and St Louis?
The best connecting points are Denver (DEN), Phoenix (PHX), Las Vegas (LAS) and Salt Lake City (SLC). Frontier Airlines flies both legs via Denver, so you can book it as one ticket.
Which airports serve Ontario and St Louis?
Ontario: Ontario International Airport (ONT). St Louis: St. Louis Lambert International Airport (STL).
What is the time difference between Ontario and St Louis?
St Louis is 2 hours ahead of Ontario.
