Cheap Flights from St. Louis to Denver

FAQ

• What are the cheapest flights from St. Louis to Denver (STL-DEN)?

  Based on Trip.com data, Frontier Airlines offers one-way fares as low as IDR 959,888 on Cheapest nonstop routes (e.g. STL to DEN on Mon, Sep 22), while Frontier Airlines offers Cheapest nonstop round-trips from IDR 860,907 departing on Thu, Oct 2 and returning on Tue, Oct 7.

• How long is the flight from St. Louis (STL) to Denver (DEN)?

  It takes about 2 hours 36 minutes to fly from St. Louis (STL) to Denver (DEN).

• When is the best time to book flights from St. Louis to Denver?

  By analyzing data from all airlines on the Trip.com flight calendar, it looks like the best time to book a flight from St. Louis to Denver is around 40 days (6 weeks) in advance, and the best time to fly is usually on Tuesday, Wednesday, and Saturday. Tuesday typically offers the cheapest flights for departure, while Saturday offers the best return deals.

• How can I find the best deals on flights from St. Louis to Denver?

  To find best deals on flights from St. Louis to Denver, you can use various tools on Trip.com:
  · Be flexible with your travel dates to get the cheapest flight deal. Now the cheapest flight deal is on Mon, Sep 22, with one-way flights priced at just IDR 959,888.
  · Compare airlines strategically. Budget carriers often provide the lowest base fares, while we found the most affordable airline currently operating on this route is Frontier Airlines.
  · Set up price alerts to easily monitor ticket prices without having to check every day.
  · Check Trip.com flight deals and promo codes frequently.
  · Avoid peak season unless you book very early. It seems the peak season for Denver travel is around June.
  · Get exclusive promo codes for Trip.com app users.

• When are flight tickets from St. Louis (STL) to Denver (DEN) the cheapest?

  The cheapest months to fly from St. Louis to Denver is April, when demand for travel is lower.

• Which upcoming date is cheapest to fly from St. Louis to Denver on?

  After crunching the numbers on our September flight calendar, it's currently cheapest to fly from St. Louis to Denver on September 29, 2025 with Frontier Airlines, with prices starting at IDR 1,445,585.

• Is there any time difference between St. Louis and Denver?

  The time difference between Denver and St. Louis is 1h.

• How do I change or cancel my ticket from St. Louis to Denver?

  Tickets can only be changed or cancelled if permitted by airline policy. To submit a change or cancellation request, go to the flight bookings page, select the option to change or cancel your booking, choose the relevant passengers and segment, and submit a request. Please note that additional charges may apply according to the airline ticket policy. However, if the flight has been rescheduled and you would like to change or cancel your ticket, you can submit an involuntary cancellation request. For more details about change and cancellation policies, please check the customer support pages.