Flights St Louis → Denver
As of October 2026, economy flights from St Louis to Denver have a typical range USD 892–1032, median USD 902. Full range across all 266 offers: USD 355–1140. We analyzed 266 offers from 7 airlines in a single price check.
Preview snapshot — prices change. Search for live results.
Data collected by LetsFG's multi-source price checks — every airline and the major booking sites checked for this route. How we collect data →
Best offers by airline: St Louis → Denver
Based on 266 offers · October 2026. Prices and availability change — run a live search to confirm.
Bag & seat fees: St Louis → Denver
Add-on pricing from the cheapest available offer per airline · October 2026 · USD
| Airline | Carry-on | Checked bag | Seat selection |
|---|---|---|---|
| Frontier Airlines | — | — | — |
| Southwest Airlines | Included | Included | — |
| United | Included | USD 35 | — |
| American Airlines | Included | USD 35 | — |
| Delta | Included | USD 35 | — |
| Alaska Airlines | Included | USD 35 | — |
Fees are estimates from the prices we checked and may not reflect your specific itinerary, booking class, or payment method. Run a live search for exact pricing.
How much do flights from St Louis to Denver cost?
Based on 266 offers · October 2026
St Louis to Denver flights ranged from USD 355 to USD 1140 across 266 offers analyzed in October 2026. The chart below shows how prices distributed across all 266 offers.
These 266 offers (October 2026) span multiple departure dates and booking windows — your travel dates may fall anywhere in this distribution. Only a live search shows where your specific trip lands.
50% of offers priced between USD 902 and USD 902
What hidden fees do St Louis to Denver flights charge?
Ancillary fees — bags, seat selection, and payment surcharges — can add 10–25% to the base fare on St Louis to Denver routes. The breakdown below is based on 266 offers analyzed in October 2026.
| Carrier | Avg fee (USD) | % of base fare |
|---|---|---|
| F9 | 10 | 2% |
| WN | 16 | 2% |
| UA | 45 | 5% |
| AA | 45 | 5% |
| DL | 45 | 5% |
| AS | 45 | 4% |
United Airlines: base ~USD 857 + fees USD 45 = ~USD 902 total. Southwest Airlines: base ~USD 886 + fees USD 16 = ~USD 902 total.
United Airlines's USD 45 ancillary fees narrow the gap with Southwest Airlines's lower-fee model — the USD 29 base difference shrinks to USD 0 after fees. Always compare total cost, not just the advertised base fare.
Estimates based on median total minus average ancillary fee. Actual base fares vary by itinerary.Fee levels vary significantly across carriers on this route — some carriers charge 50%+ above the base fare in ancillary fees.
Run your search to see itemized fees for your itineraryWhich airline is cheapest from St Louis to Denver?
7 airlines flew St Louis to Denver in this dataset. Knowing the airline isn't enough — the typical fare range below shows how far prices swing on each one. Median and range include all fees we recorded.
Even on the cheapest airline (Frontier), fares ranged USD 355–602 in this snapshot. Your exact price depends on your dates and how far ahead you book — run a live search to see your number →
| Airline | Offers | Typical range (USD) | Median (USD) | Fees (USD) |
|---|---|---|---|---|
 Frontier | 6 | 355–602 | 400 | n/a |
 Frontier Airlines | 7 | 355–503 | 425 | 10 (2%) |
 Southwest Airlines | 149 | 892–1032 | 902 | 16 (2%) |
 United Airlines | 75 | 892–902 | 902 | 45 (5%) |
 American Airlines | 13 | 911–1095 | 911 | 45 (5%) |
 Delta Air Lines | 14 | 961–993 | 961 | 45 (5%) |
 Alaska Airlines | 2 | 1067–1076 | 1072 | 45 (4%) |
Where do the best St Louis → Denver prices come from?
We checked direct airlines, travel agencies, and meta-search for this route. On this route the lowest median came from travel agency sources, but the cheapest channel shifts by route and date — which is exactly why a live search across all of them wins.
We compare every airline and the major booking sites but never disclose which — that's our edge. Prices are the ones we observed and aren't official data from any platform. Run a live search and we bring you the cheapest, wherever it is.
Key facts: St Louis to Denver flights
- Full-service carriers on St Louis–Denver cost 1.7x more than budget airlines (USD 961 vs USD 575 median; overall median USD 902).
- UA charges 4.5x more in ancillary fees than F9 — USD 45 vs USD 10 avg per booking.
- The same route priced USD 643 apart depending on where it was booked — the lowest median was USD 400. We search every airline and the major booking sites at once so you always see that lowest price.
Frequently asked questions
- How much does a flight from St Louis to Denver cost?
- Based on 266 offers analyzed, St Louis to Denver flights range from USD 355 to USD 1140, with a median price of USD 902. Search for your specific dates →
- What hidden fees should I expect on St Louis to Denver flights?
- On average, ancillary fees (bags, seat selection) add USD 27 to the base fare on St Louis to Denver flights. See itemized fees for your itinerary →
- Which airline is cheapest on St Louis to Denver including all fees?
- Frontier has the lowest median fare on St Louis to Denver at USD 400 (median across 6 offers in our snapshot). Check which airline wins on your dates →
- Which booking site has the cheapest St Louis–Denver flights?
- It depends on your dates — no single site is always cheapest. We search every airline and the major booking sites at once (travel agencies and meta-search included) and surface whichever is lowest; the best median in this snapshot was USD 400. Run a live search and we'll find the cheapest for you →
- Why do prices vary so much on St Louis to Denver routes?
- St Louis to Denver has 7 airlines competing, creating a price range from USD 355 to USD 1140 across 266 offers. Prices on this route change with booking timing, advance purchase, and ancillary add-ons. Find where your trip lands in the distribution →
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