Your next trip, last seen at €41
Frontier Airlines · Non-stop · One wayWhen to fly
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The lowest fare we observed for each month. Open a month to see its days, then pick your outbound and return. A day with no price is one we will search for you.
- Airlines seen
- Frontier Airlines, Southwest Airlines, American Airlines, Southern Airways Express, United Airlines
- Reported fastest flight
- 2h 22m
- Non-stop
- Yes
About this route
Explore the fares we observed from St Louis to Denver. Prices move often, so pick your dates to see the latest options.
- Route distance
- 1,279 km
- Reported fastest flight
- 2h 22m
- Airlines seen
- Frontier Airlines, Southwest Airlines, American Airlines, Southern Airways Express, United Airlines
- Alternative airports
- SUS, APA
Route-level information; individual journeys vary.
Published schedules report non-stop service with Frontier Airlines, Southwest Airlines. Check current timetables.
A clearer picture of your fare
Non-stop airlines seen on this route
| Airline | Non-stop days / priced days | Fastest non-stop |
|---|---|---|
| Frontier Airlines | 44 / 91 | |
| United Airlines | 11 / 91 |
Departure days with a non-stop fare checked in the last 14 days. A carrier listed here had a non-stop fare on at least 3 days; schedules may differ.
Airport to city: straight-line distance
- St. Louis Lambert International Airport (STL) → St Louis, city gazetteer reference point (38.6270, -90.1994): ≈ 20 km.
- Denver International Airport (DEN) → Denver, city gazetteer reference point (39.7392, -104.9847): ≈ 30 km.
Approximate distances calculated from coordinates, not road distances or travel times. These airports serve the city; they are not confirmed endpoints of an offer.
Lowest one-way fare we saw per airline
Cheapest airline from St Louis to Denver: Frontier Airlines, from €39 (checked 12 Oct 2026).
| Airline | Lowest fare | Priced days |
|---|---|---|
| Frontier Airlines | €39Dec 7, 2026 | 79 |
| United Airlines | €124Nov 3, 2026 | 11 |
One-way fares checked in the last 14 days. An airline listed here had a fare on at least 3 departure days. Each figure is the lowest we saw, not a guaranteed fare. Connecting itineraries are included; the date is the departure day of that fare.
Frequently asked
How much was a flight from St Louis to Denver?
A fare of €77 was seen on 9 Sep 2026. Fares change, so search your dates for the current price.
Are there direct flights from St Louis to Denver?
Yes. We have seen non-stop flights on this route, flown by Frontier Airlines, Southwest Airlines.
Which airlines fly from St Louis to Denver?
These are the carriers we have seen on the route: Frontier Airlines, Southwest Airlines, American Airlines, Southern Airways Express, United Airlines.
How long does the flight from St Louis to Denver take?
The average journey time across the 71 fares we observed is 8h 37m, including any stops. Individual departures vary; the fastest observed flight is listed in the route facts above.
How many of the observed St Louis to Denver fares were non-stop?
39 of the 71 fares we observed were non-stop; the rest included at least one stop. That describes our observations, not every flight that operates.
Which airlines had non-stop offers on at least 3 departure dates from St Louis to Denver?
For St Louis to Denver, examples of observed one-way non-stop offers checked within the last 14 days: Frontier Airlines (44), United Airlines (11). Each number counts distinct departure dates, not weekly flights; check current availability in search.
Which airline has the lowest fare from St Louis to Denver?
Cheapest airline from St Louis to Denver: Frontier Airlines, from €39 (checked 12 Oct 2026).
How observed prices work, what "No data" means and what a fare includes: Read the flight price guide
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Recently observed fares. Prices may change.
Last checked: 9 Oct 2026