$78 Find Cheap Flights from St. Louis to Denver - Compare and Save

Frontier and United operate several nonstop flights from STL to DEN that depart throughout the day. American and United operate several flights per day that have one stop. The layover for these flights is often in cities such as Chicago (ORD), Charlotte (CLT), and Dallas (DFW).

STL provides a USO lounge for active military service members and their families. The James S. McDonnell USO, located in Terminal 1 on the lower level opposite M6 baggage claim, is open 24h a day, 7 days a week, 365 days a year. All services and amenities at the USO are without charge. Some of these offerings include beverages, snacks, Wi-Fi, a DSN phone, laptops, and computers. You can also relax by watching cable TV, watching a DVD or a Blu-ray disc, or playing Xbox 360. The USO also has a seating area, a quiet area where you can sleep, a nursery, and toiletries.

STL provides dedicated private spaces to mothers who want to nurse or breast pump in clean privacy. These lactation suites are located past security at Gates A10, C9, and E33. Each calm, clean room has power outlets for a breast pump, a sink, and a full back comfortable chair with a movable arm table. There is also an Ottoman and a bench so that additional people, such as baby’s siblings, can join mama in the space, with enough room for luggage.

You can take the A Line of the RTD bus that runs to the center of Denver. Also, you can take a train that departs from DEN 4 to 6 times an hour. Public transportation from DEN is very convenient to get you into downtown Denver.

Among airlines operating St. Louis to Denver flights:

• Frontier: offers free seat selection
• United Airlines: offers extra legroom; offers free seat selection
• Southwest: offers free seat selection

Extra legroom and free seat selection availability depends on fare class and route.

3 airlines operate flights between St. Louis and Denver. The airlines offering nonstop flights on this route include:

• Southwest
• United Airlines
• Frontier

Flights from St. Louis to Denver usually depart from Lambert-St Louis (STL) and arrive at Denver Intl (DEN).

Here are some options for this route, based on selected ticket types and cabin classes:

• United Airlines: a cabin bag and a checked bag in Economy Class
• Frontier: a cabin bag in Economy Class class
• Southwest: a cabin bag in Economy Class class

Bag allowance can vary by ticket type, cabin class, route and airline, so travelers should check the fare details before booking.

Two cabin classes are available on flights from St. Louis to Denver:

• Economy Class
• First Class

On this route, layover flights are cheaper than nonstop options on average. Layover fares average $182 round-trip via Kansas City (MCI), compared to $268 for nonstop.

There is no standard. Checked-bag policies vary by airline on this route. Most carriers charge $40–$100 for the first checked bag in economy. Premium fares and elite-status bookings typically include a free checked bag.

The Boeing 737 MAX 8 family is used most often on this route, operated mainly by Southwest. Other aircraft seen on the route include Boeing 737-800 Passenger/BBJ2 (winglets) variants.

One-stop flights from St. Louis to Denver most commonly connect through:

• Dallas/Fort Worth (DFW) - 59% of one-stop connections
• Atlanta Hartsfield-Jackson (ATL) - 9% of one-stop connections
• Las Vegas Harry Reid Intl (LAS) - 9% of one-stop connections
• Kansas City (MCI) - 9% of one-stop connections

Dallas/Fort Worth (DFW) handles the largest share of one-stop connections on this route.

On the St. Louis to Denver route, being flexible with your departure day can save you up to 35%. Saturday is the cheapest day at $215 round-trip on average, while Sunday is the most expensive at $329: a $114 difference. Cheaper weekend fares like these are typical of routes dominated by weekday business travel.

Morning is the busiest departure period on St. Louis to Denver flights, with 40% of flights leaving in that window. Afternoon departures account for 40%, evening flights for 20%, and night flights for 0%.

Some of the most popular sights in Denver are Colorado Convention Center, Union Station Denver and Coors Field. These are among the most viewed places in Denver on KAYAK.

These are the earliest and latest flight times available from St. Louis to Denver:

• Earliest: departs at 5:10 am and lands at 7:35 am
• Latest: departs at 10:50 pm and lands at 1:15 am.

The flight takes about 2h 25m.

Last-minute fares on this route - booked within 2 weeks of departure - run 23% above the route average of $266. Book 6 weeks before departure for the lowest fares.

A nonstop flight from St. Louis to Denver takes 2h 25m, covering 767 miles.

No, a passport is not required for this domestic route, but you will need a real ID-compliant driver's license, a state ID, or another TSA-accepted form of identification.

One-way fares from St. Louis to Denver are currently lower than usual. Average one-way flight prices are about $88, which is 50% below the typical average for this route.

Flying via Kansas City (MCI) gives the shortest average 1-stop total travel time at 5h 04m, compared with 5h 10m via Minneapolis St Paul (MSP) and 5h 14m via Chicago O'Hare Intl (ORD).

Denver is 1 hour behind St. Louis (Mountain Time vs Central Time). Plan for the time shift when scheduling connections or first-day activities.

Denver Intl Airport (DEN) hosts 5 major car rental companies, with daily rates starting from around $16 for economy cars. Top options include:
• Routes Car & Truck Rentals
• Ace
• NU Car
• Europcar
• Hertz

Round-trip flights from St. Louis to Denver range from $167 to $363, with an average of $266 over the past 12 months. Anything below $167 counts as a good deal.

JetBlue is the only airline on the St. Louis to Denver route offering in-flight Wi-Fi. Pricing depends on fare class.