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Home / St Louis — Ontario

Cheap flights St Louis — Ontario

St Louis (STL, US) Ontario (ONT, US)
from $137 2 500 km ~3h 26m 2 flights found 1 airlines cheapest on Friday
Reverse route
How many travellers?
Adults
12+ years
1
Children
2–11 years
0
Infants
under 2
0
Choose your departure date
Cheapest: $137 on 18.12.2026
Prices shown are from searches by other travellers over the last 24 hours. Missing a date? Click any day — we'll find tickets anyway.
November 2026
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December 2026
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January 2027
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Prices found for 2 of 90 days. Prices update as more travellers search. Click any date to search live.
Depart
—
Return
—
Cheapest flights found
18 Dec 2026, Fri
Frontier Airlines F9 3107
02:45
STL Lambert-St. Louis International Airport
07:37
ONT Ontario International Airport
4h 52m 1 stop
Farera
$137
View this ticket
15 Nov 2026, Sun
Frontier Airlines F9 4567
04:59
STL Lambert-St. Louis International Airport
09:52
ONT Ontario International Airport
4h 53m 1 stop
Farera
$199
View this ticket
Route characteristics
Distance
2 500 km
Flight time
3h 26m
Time difference
-2h
Minimum price
from $137 (18.12.2026)
Average price
$168
Maximum price
$199
Cheapest day
Friday
Departure airports (1)
STL Lambert-St. Louis International Airport
Arrival airports (1)
ONT Ontario International Airport
Airlines (1)
F9 Frontier Airlines
Agencies (1)
Farera
Prices by day of week
Friday
$137
avg $137
Cheapest
Sunday
$199
avg $199
Price trend by month
November 2026
from $199
avg $199
1 flights
December 2026
from $137
avg $137
1 flights
Airlines — cheapest prices 1
Frontier Airlines
Frontier Airlines
Low-cost 2 flights · 2 days
$137
Where to buy tickets 1
Farera
2 tickets · 2 days
from $137
Airports

From — St Louis (1)

  • STL Lambert-St. Louis International Airport

To — Ontario (1)

  • ONT Ontario International Airport
Other destinations from St Louis
Burlington
US
Decatur
US
Jonesboro
US
Cape Girardeau
US
Kirksville
US
Marion
US
Owensboro
US
Fort Leonard Wood
US
Quincy
US
Dallas
US · Hub
Los Angeles
US · Hub
Miami
US · Hub
Frequently asked questions about the route St Louis — Ontario
How long is the flight from St Louis to Ontario?
Approximate flight time — 3h 26m. This is an average for a direct flight. With connections, the time may be longer.
What is the distance from St Louis to Ontario?
The straight-line distance — 2 500 km.
How much do flights from St Louis to Ontario cost?
The minimum price over 3 months — from $137 on 18.12.2026.
What is the average ticket price?
The average price — $168. Range: $137 — $199.
What is the time difference between St Louis and Ontario?
The difference — -2h.
From which airports does St Louis operate flights?
From St Louis: STL (Lambert-St. Louis International Airport).
To which airports in Ontario do flights arrive?
To Ontario: ONT (Ontario International Airport).
Which airlines fly this route?
This route is served by 1 airline: Frontier Airlines.
Which day of the week is cheapest?
The cheapest day of the week — Friday.
When is the best time to buy tickets?
Optimal — 1–3 months before departure. Check the calendar above — it shows the best dates.
How do I book flights?
Click "View this ticket" on any flight card — you'll be redirected to the booking page with this specific ticket pre-selected.
About the route St Louis — Ontario

Flights St Louis — Ontario is a popular route. The straight-line distance is 2 500 km. Flight time 3h 26m. Time difference -2h.

From St Louis (STL) flights depart from 1 airport: STL. To Ontario (ONT) — 1 arrival airport: ONT.

1 airline operate on this route: Frontier Airlines.

The minimum price for the next 3 months — from $137 (18.12.2026). The cheapest dates are highlighted in the calendar above.

The average ticket price — $168, ranging from $137 to $199. Book 1–3 months in advance to get the best deals.

Cheapest day to fly — Friday.

Other destinations in United States from St Louis
Burlington
US
Decatur
US
Jonesboro
US
Cape Girardeau
US
Kirksville
US
Marion
US
Owensboro
US
Fort Leonard Wood
US

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