DIA to Build Pedestrian Walkways Between All Three Concourses

Here’s what we know about DIA’s newly announced pedestrian walkway project:

Denver International Airport announced today that it will construct pedestrian walkways connecting Concourses A, B, and C for the first time in the airport’s history, giving travelers an alternative to the frequently troubled underground train system.

• What: DIA will repurpose a dormant underground baggage tunnel — adjacent to the existing train tunnel — into pedestrian walkways.
• Construction start: 2027, with design work beginning this year.
• Estimated cost: Between $300 million and $700 million, according to Denver Mayor Michael Johnston.
• Walk time: Travelers could move from the main terminal to Concourse C in roughly 10 to 15 minutes, faster if moving sidewalks are included.
• Why not bridges? Officials considered above-ground bridges (1,400 feet from A to B, 1,100 feet from B to C), but those would cost $2–3 billion, be far more disruptive, and take longer to build.

Why Now?

DIA’s underground concourse trains have been the sole way to travel between Concourses B, C, and the terminal (Concourse A also has a pedestrian bridge from the terminal). The trains have been plagued by reliability issues — including a notable power outage in March 2026 that caused crowds to pile up. The walkways directly address this long-standing pain point.

Airline & City Support

• Denver Mayor Mike Johnston: “We’ve heard loud and clear that easier, more reliable ways to move between concourses has been a top priority for people traveling in and out of DEN.
• United Airlines (Denver’s largest airline, operating on two concourses): VP of Airport Operations Jonna McGrath called it “a significant investment” that will “give our customers more options for their connecting flights.
• The mayor also playfully referenced the airport’s famous conspiracy theories: “The whole world has speculated for decades about what exists in the tunnels under Denver International Airport. Now, the whole world will get to see it. See more at 9news.com

Experience & Design

Officials emphasized this won’t feel like a utilitarian passage. “We want to make this a pleasing journey,” and artwork will be displayed in the tunnel. “We will make sure folks want to walk down there. It won’t be a dark alley.”