Connecting at Denver: the train, the long walks and the weather

Last checked 24 September 2026

Is a 45-minute layover enough in Denver?

We estimate about 13% of 45-minute connections at Denver (DEN) ended in a missed connection between September 2025 and August 2026. How we count a missed connection

Allow 86 minutes for a connection in the same concourse at Denver (DEN), or 88 minutes if you change concourse.

Based on U.S. Customs and Border Protection's hourly figures, passport control at Denver (DEN) averaged 12 minutes (U.S. citizens 10 minutes, non-U.S. citizens 17; September 2025 to August 2026). That figure leaves out collecting and re-checking bags and the security re-screen, which at large US hubs we estimate add about 30 to 45 minutes.

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Denver is one of the easier big hubs for security: once you're through, a domestic connection never sends you back through a checkpoint. What decides a Denver connection is distance and weather. There's one terminal and three long concourses, joined by a train that is the only way to reach B and C.

At a glance

• No second security check for domestic connections. Every concourse is joined up behind security.
• B and C are train-only. A is reachable by train or by walking from the terminal.
• Allow 5–10 minutes for the train between concourses, including the wait.
• The walk from the train platform to your gate is what catches people out, especially at the far end of a concourse.
• Watch the weather: summer afternoon storms, strong winds and extreme cold are what usually disrupt Denver connections.

Who flies from where

• Concourse A: United, Alaska, Allegiant, Delta, JetBlue and Sun Country, plus the international airlines. All international flights arrive at A.
• Concourse B: United.
• Concourse C: Southwest, Frontier and American, plus Contour and Denver Air Connection.

United flies from both A and B, so a United-to-United connection can still mean a train ride. Check both gate letters.

The train

The train links the terminal with all three concourses, behind security. It's the only way to reach B and C; there's no walkway. The airport says the trip out to C takes less than ten minutes, and trains come every minute and a half or so at peak times.

From the flight deck: On a normal day, allow 5 to 10 minutes from platform to platform, including the wait for a train.

The walk nobody plans for

Denver's concourses are long. If your next gate is near the far end of one, allow for the walk from the train platform as well as the train itself.

From the flight deck: The walk from the train to a gate at the far end of a concourse is the part that catches most passengers out. Look at your gate number before you step off the train, and head straight for it.

Weather: the part of the time budget you can't see

Denver's schedule depends on the weather. A connection that works on a calm day can get tight when your first flight arrives late.

From the flight deck:

• Summer afternoon thunderstorms can stop departures and send arrivals into holding. On summer afternoons, give yourself more margin.
• Strong winds force runway changes and cut the number of arrivals the airport can take, so inbound flights queue.
• Extreme cold is hard on aircraft, and technical delays are more likely.

A GateCast grade shows how much margin a connection has on a normal day. On a stormy July afternoon or a frozen January morning, treat a C or D as tighter than it looks.

How GateCast grades Denver connections

Because Denver connections stay behind security, the time budget is about movement. It counts getting off the aircraft, the walk to the train, the train, the walk to your gate, and the boarding cut-off for your next flight. A same-concourse connection needs much less time than a change from A to C, even with the same time on the ticket. GateCast works out the concourse from the airline. United flies from both A and B, so a United-to-United connection is scored as if both flights were in the same concourse, even when it's really a train ride between A and B. If your United gates are on different concourses, allow for the train yourself.

Tips

• Check the concourse letter for both flights. United uses A and B.
• When you step off the train, go straight to your gate. Don't browse until you know how far it is.
• In summer, prefer morning connections when you can. Storms tend to build in the afternoon.

How we count a missed connection

The layover times and missed-connection percentages on this page are estimates from our model, built on US DOT records (September 2025 to August 2026), with no guarantee; never book shorter than your airline's minimum connection time.

Each time is our model's point estimate of where the fitted missed-connection curve levels off, from past flights between September 2025 and August 2026. The curve is calculated at 5-minute steps and joined by straight lines. Giving the time to the minute does not make it more certain: when we re-ran the estimate on 200 resampled sets of days, 95% of the times at Denver (DEN) for staying in the same concourse fell between 79 and 91 minutes, and for changing concourse between 59 and 98 minutes.

A missed connection means the real delays and cancellations that day left less time than our estimate of how long the change takes; estimated from US DOT on-time records for September 2025 to August 2026, with no passenger data.

The 45-minute figure is the estimated share of connections at Denver (DEN) that ended in a missed connection. The time in the box is the shortest layover after which another 15 minutes lowers the estimated missed-connection rate by less than 1 percentage point, on a curve fitted so that it never rises. The 1 percentage point is a judgement constant that we set. Extra time helps less and less because cancellations and long delays cause missed connections at any gap. At Denver (DEN), the estimated missed-connection rate was 5.8% at 86 minutes if you stay in the same concourse, and 8.2% at 88 minutes if you change concourse (and 6.0% at 2 hours) (share of connections, September 2025 to August 2026). We don't give a figure for 30 minutes. A 30-minute connection is about as long as our own estimate of the change (typically 26 to 31 minutes at one terminal) and often shorter, so a percentage would mostly come from that estimate.

The passport-control figure is our average of U.S. Customs and Border Protection's hourly averages at Denver (DEN), weighted by passengers, for flights arriving between September 2025 and August 2026 (CBP Airport Wait Times, awt.cbp.gov, downloaded 22 October 2026). CBP says its wait times "do not include time to retrieve baggage or navigate through the airport." The 30 to 45 minutes for bags and the security re-screen is our rough estimate for large US hubs, based on airlines' stated savings of up to 25 minutes for bag transfer and up to 45 minutes for skipping the re-screen in their international-connection trials, and on traveller reports; actual times vary widely and we have no figure for Denver (DEN) alone.

Checked 24 September 2026; layover figures checked 23 October 2026; passport-control figures checked 22 October 2026. Airlines and concourses change, so confirm with your airline before you travel.

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