Route guide · 768 miles
Cheap Flights from St. Louis to Denver
STL → DEN · Nonstop 2h 4m · Live round-trip fares
Flying from St. Louis to Denver doesn't have to drain your wallet. This 768-mile hop takes about 2h 4m nonstop, and fares swing a lot depending on the week you pick. Travelers who book roughly 2–4 weeks out usually come out ahead — set a free alert and let the deals come to you.
Live fares for STL → DEN are updating. Use the search below for real-time prices.
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Flight time
2h 4m
Nonstop, typical
Distance
768 mi
STL → DEN
Book ahead
2–4 weeks
Best window, typically
Nonstop airlines
3
Frontier Airlines, United Airlines & more
Nonstop flights from St. Louis to Denver
Nonstop service links St. Louis and Denver directly — flights are flown by Frontier Airlines, United Airlines, Southwest Airlines. Expect roughly 2h 4m in the air. If a nonstop is what you want, don't wait too long: booking 2–4 weeks ahead is when these seats are priced most kindly.
Booking insights: St. Louis → Denver
- Distance: 768 miles · nonstop flight time: 2h 4m.
- Rule of thumb for this route: the sweet spot is usually 2–4 weeks before departure.
- If your dates flex by a day or two, shifting to a midweek departure is the easiest saving there is.
- Set a free Airfare Deal alert instead of checking daily — the best fares can sell out in hours.
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Flying from St. Louis to Denver: what you need to know
The flight
St. Louis to Denver covers 768 miles, and a nonstop gets it done in about 2h 4m. That's long enough to settle in with a coffee and a downloaded show, short enough that a connection rarely makes sense — a layover usually doubles your travel day to save very little.
Airlines on this route
Frontier Airlines, United Airlines and Southwest Airlines fly this route nonstop. That matters more than it sounds: the cheapest fare on one carrier is rarely the same product as the cheapest on another. Checked-bag fees, free seat selection and change rules all differ, so compare the full trip cost before you pick a winner. See our airline guides for exactly what each carrier charges — then send an enquiry and we'll confirm the all-in price for your dates.
Leaving from St. Louis (STL)
Plan to be at the airport two hours before a domestic departure — ninety minutes can work at smaller airports outside peak times, but security lines are the one variable you can't control. If you're checking a bag, add time rather than cutting it close. Our St. Louis airport guide covers terminals, parking and ground transport so you can plan the trip to the airport, not just the flight.
Arriving in Denver (DEN)
Before you land, know how you're getting from the airport to where you're staying — it's the part of the trip people forget to plan. The Denver airport guide lays out your ground options, from transit and shuttles to rideshares and rental cars. Flying back the other way? Check Denver to St. Louis fares — prices on the return direction often move on a different rhythm.
When to book
For a trip of 768 miles, booking 2–4 weeks ahead typically lands you in the sweet spot. Leave it to the final two weeks and prices usually climb as the cheapest seats sell out. If your dates are flexible, midweek departures are where the lower fares hide on most domestic routes.
Good to know before you go
- Get to the airport two hours before departure; security, not the flight, is the part that runs late.
- If you're traveling with only a carry-on, you can skip the bag-drop line entirely with mobile check-in.
- Download the airline's app before you fly; gate changes and delays show up there first.
- Nonstop time on this route is about 2h 4m — a one-stop itinerary needs to be a lot cheaper to be worth the extra hours.
- Tuesday and Wednesday departures are typically the cheapest days on domestic routes.
St. Louis to Denver flight FAQs
How long is the flight from STL to DEN?
A nonstop from STL to DEN clocks in at around 2h 4m for the 768-mile trip. If you're connecting, budget an extra 2–4 hours depending on where you stop.
Are there nonstop flights from St. Louis to Denver?
Yes — look for Frontier Airlines, United Airlines, Southwest Airlines on this route. Nonstop seats are usually priced best 2–4 weeks before departure.
What is the cheapest month to fly from St. Louis to Denver?
Fares from St. Louis to Denver tend to ease outside the peak summer and holiday rush — the late-summer and early-fall shoulder weeks are usually kinder on the wallet. Set a free Airfare Deal alert and we'll flag the dips for your dates.
How much are last minute flights from STL to DEN?
Book inside the final week and you'll usually pay a premium on STL to DEN. Fares booked 2–4 weeks ahead are almost always kinder.
What is a good round-trip deal from St. Louis to Denver?
A good deal is anything at or below the recent fares shown above. Set a free Airfare Deal alert and we'll ping you the moment fares drop.
Which airlines fly from St. Louis to Denver?
The main carriers on this route are Frontier Airlines, United Airlines, Southwest Airlines. Comparing all of them on the live search below usually surfaces the lowest fare for your dates.
How early should I get to St. Louis airport for this flight?
Plan on two hours before departure for a domestic flight — ninety minutes can work at smaller airports outside peak times. If you're checking a bag, earlier is better; the bag-drop line, not the flight, is what runs late.
Do the cheapest fares on this route include a checked bag?
Usually not. Basic economy fares on most airlines include a carry-on but charge extra for checked bags, and seat selection can cost more too. Add up the real total before comparing — a slightly higher regular fare sometimes works out cheaper. Our team confirms the full breakdown with you before you pay.
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