CA $138 Cheap Flights from St. Louis (STL) to Denver (DEN)

You can find one-way and return flights from STL to DEN with Expedia. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see our cheapest fares first, and use the Price Tracking tool to receive alerts when STL to DEN ticket fares go up or down.

The cheapest months to fly from St. Louis, MO (STL) to Denver, CO (DEN) are typically during off-peak season when demand is low. Traveling in off-peak or shoulder months is usually a good way to secure cheap tickets, just remember to avoid flying during holidays if you are able to. Use the calendar view in your search to see which months have low fares on this route.

There are 3 airlines offering direct flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.). These include:
* Southwest Airlines operates 47 direct flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) every week.
* United operates 41 direct flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) every week.
* Frontier Airlines operates 7 direct flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) every week.

Frontier Airlines is one of the cheapest airlines offering nonstop return flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.), with tickets starting from around CA$66 for flights that can be booked for departure within the next year. Southwest Airlines offers one of the cheapest connecting return flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) with a layover in Love Field (DAL), starting from around CA$170. These prices are per adult for economy/coach class. Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.

To find a cheap flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.

The best airline to fly with from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) will differ from traveler to traveler. If you like to fly early, Southwest Airlines offers early morning flights. If price is the most important factor, Frontier Airlines typically offers the lowest fares. Southwest Airlines offers the most daily flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.), which is great if flexibility is what you value most. The best carrier for this journey could also be the one you have a loyalty membership with, as flying with that airline or another airline within the same alliance could help you collect points or enjoy lounge access.

The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.

You'll find approximately 13 nonstop flights per day from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.). For even more choices, look at flights that include layovers, as there are around 148 connecting flights daily. Some common connection points include O'Hare Intl. (ORD), Seattle - Tacoma Intl. (SEA), and Dallas-Fort Worth Intl. (DFW).

The earliest flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) typically departs around 5:00 AM. This service is operated by American Airlines. This is a seasonal service, active in January, November, and December. An early departure like this can help you make the most of your time at your destination. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.

You'll typically find the most flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) on a Friday, with around 102 flights available. This gives you plenty of options for your travel plans. Major airlines on this route include Southwest Airlines, United, and Delta. Friday offers notably more flight options compared to other days of the week, making it a great day to find a flight that fits your schedule.

The most popular departure times for flights from Lambert-St. Louis Intl. (STL) to Denver Intl. (DEN) are in the early morning, from 6am to 9am. Many major carriers, including Southwest Airlines, American Airlines and Delta, offer flights during this window. Many travellers prefer these times because it allows them to arrive in Denver early, giving them a full day to enjoy their destination.

A direct flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) typically takes around 2 hours 30 minutes. This route covers a distance of approximately 1,236 kilometers. If you opt for a one-stop flight, your journey will usually take longer, around 6 hours. Flights with two or more stops will extend your travel time even further, to about 9 hours 50 minutes. Keep in mind that actual flight times can vary due to factors like wind patterns and air traffic, so it's always a good idea to allow for some flexibility in your travel plans.

You can fly business class or first class between STL and DEN. Airlines that offer business class service on this route include:

* Frontier Airlines
* Delta

First class cabins are available on Alaska Airlines, United, Delta, and American Airlines.

It's easy to earn miles on a St. Louis, MO (STL) to Denver, CO (DEN) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.

*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.

If you're planning to travel to Denver from Lambert-St. Louis Intl. (STL), you can fly directly into Denver Intl. (DEN). Some flights may connect through major hubs like Seattle - Tacoma Intl. (SEA), Love Field (DAL), or Midway Intl. (MDW) before reaching Denver. Compare routes and airports on Expedia to find the best flight options for your travel plans.

Typically, booking a last minute flight from St. Louis, MO (STL) to Denver, CO (DEN) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.

Securing a St. Louis, MO (STL) to Denver, CO (DEN) flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.

If you booked your St. Louis, MO (STL-Lambert-St. Louis Intl.) to Denver, CO (DEN-Denver Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.