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

Last checked 24 September 2026

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 more than most hubs. 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.

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.

Checked 24 September 2026. Airlines and concourses change, so confirm with your airline before you travel.