In the past year, the trains connecting travelers to Concourses B and C at Denver International Airport have stopped working 131 times, largely due to the installation of new cars that began entering service in June 2024. The outages, which often make headlines, cause chaos and backups in Concourse A and make travelers worry they’re going to miss their flights.
Now, airport leaders say they have come up with a solution. They plan to convert part of the airport’s underground baggage tunnels into walkways, allowing travelers to walk to all gates for the first time ever. The walkways will also serve as a backup plan for the train system, in case it malfunctions again in the future.
The details are still being finalized, but airport leaders say they expect construction to begin sometime next year and last between 18 and 24 months. The project could cost anywhere between $300 million to $700 million, based on factors that have yet to be decided, such as whether to install moving sidewalks or add additional retail and concession space.
“This is a big win for Denver’s travelers and for our entire community,” says Mike Johnston, mayor of Denver.
After passing through TSA security, travelers can already walk to Concourse A should they so choose. But, for all of the airport’s 31-year history, the only way to reach Concourses B and C has been via train.
Soon, they’ll be able to walk from the terminal to Concourses B and C. The entire journey is expected to take roughly 10 to 12 minutes at a normal walking pace.
“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,” says Johnston. “These new pedestrian walkways would deliver on that—giving folks more flexibility while we continue building one of the best-connected airports in the world.”
“And who knows… maybe along the way, travelers will finally get a closer look at the underground tunnels and decide for themselves what’s fact and what’s fiction,” he adds, a cheeky reference to the various conspiracy theories swirling around the airport.
The upgrades couldn’t come at a better time. In 2025, Denver International Airport had its busiest year ever, serving a record 82,427,962 passengers during the year. That represents a 0.1% increase over 2024. Much of that growth was driven by international passenger traffic, which increased 4.8 percent over 2024. Overall, DEN welcomed a record-high 4,867,484 international passengers, who made up 5.9 percent of DEN’s total passenger traffic.
The numbers mean DEN is now the fourth-busiest airport in the U.S. and the 10th busiest airport in the world.
“As DEN continues to increase passenger numbers and global connections, we are committed to providing customers with the best airport experience,” says Phil Washington, chief executive officer of Denver International Airport. “Adding pedestrian walkways to DEN’s current infrastructure is another key component of our Vision 100 plan.”
Vision 100 represents the first phase of the airport’s strategic plan, as leaders focus on preparing the airport to serve 100 million annual passengers in the next several years. The pedestrian walkways should help the airport accommodate additional guests now and in the future.
Airport leaders made the decision to invest in pedestrian walkways after spending three years weighing all the possible options. They also considered a gondola system, self-driving pods and elevated bridges above the tarmac. The gondola and bridge options haven’t been entirely ruled out for the future.
The pedestrian walkways have support from airlines that regularly fly into and out of Colorado, including United Airlines, Southwest Airlines and American Airlines.
“The addition of pedestrian walkways adds flexibility and reliability for our customers and improves operational resilience,” says Amanda Zhang, vice president of corporate real estate for American Airlines.
The new pedestrian walkways are just one of the ways the airport has been working to improve its infrastructure and service in recent years.
The airport has also added 39 new gates across all three concourses and is in the process of renewing the older areas of existing concourses. The airport has also invested more than $75 million into its train system, with additional new train cars and other system upgrades on tap in the coming years.
Crews are also refreshing the Great Hall refresh inside of Jeppesen Terminal, with work scheduled for completion in 2027. The goal is to make the Great Hall feel more welcoming, peaceful, flexible, functional and unique and authentic to the culture of Colorado.
“It’s rare to have an opportunity to reconstruct a major airport terminal and to modernize and reimagine it for the needs of today’s travelers as well as travelers of the future,” says Washington. “But the Great Hall Program is allowing us to do just that. The final phase will result in an iconic space inspired by the natural beauty of Colorado designed to leave a memorable first and last impression.”
