Denver International Airport (DEN) sits a long way out on the plains east of the city — around 40 km from downtown — but a direct commuter rail line makes the transfer straightforward and largely traffic-proof, running right into the heart of Denver's Union Station in under an hour.
The standard way: the A Line to Union Station
The A Line, part of the Regional Transportation District's (RTD) commuter rail network, runs directly from a station inside the airport terminal to Union Station in downtown Denver, taking around 35–40 minutes end to end. Trains run frequently throughout the day, calling at a handful of suburban stops along the way, and because it operates on its own dedicated track rather than sharing the road with commuter traffic, the journey time stays consistent regardless of how backed up the interstates are.
Fares are paid with an RTD MyRide card, a contactless bank card tap where accepted, or through the RTD mobile app, and no reservation is required — simply board the next train. Given the distance involved, the A Line is usually both the fastest and the cheapest way into the city for anyone not renting a car straight away.
Buses
RTD also runs bus routes connecting the airport to parts of the metro area the A Line doesn't reach directly, useful if your destination is a suburb rather than downtown itself. These tend to take longer than the train given more stops and mixed road traffic, but can be a cheaper or more direct option depending on exactly where you're headed.
Rideshare and taxis
Uber and Lyft operate from a designated pickup area a short walk from the terminal. Given DEN's distance from the city, a rideshare into downtown typically takes 45 minutes to an hour, and considerably longer during rush hour on the interstates connecting the airport to Denver proper — a case where the A Line's fixed journey time is a real advantage over a car covering the same distance. Metered taxis are also available from a marked rank, generally at a similar or slightly higher cost than rideshare for the same trip.
Car hire at the airport
DEN has a large consolidated rental car facility a short walk or shuttle ride from the terminal, and a rental car is genuinely useful here beyond just the transfer — Denver is the natural gateway to Rocky Mountain National Park, the ski resorts of the I-70 corridor, and a wider road trip through Colorado's mountains, none of which the train network covers. For getting into and around downtown Denver itself, though, the A Line is simpler and avoids paying for parking in the city centre. See our guide to driving in the USA for the basics of renting and driving.
Why the distance matters here
DEN was deliberately built far from the city on open land, partly to allow room for expansion and reduce noise complaints, and it remains one of the more remote major airports in the country relative to its downtown. That distance is exactly why the A Line matters so much for this particular transfer — on a shorter airport-to-city hop a car might comfortably compete with rail on time, but over roughly 40 km of highway, a dedicated train line has a much bigger built-in advantage.
If winter weather delays your flight, DEN has a reasonable spread of airside facilities to wait it out — see our guide to how to get into airport lounges and, for a longer overnight disruption, sleeping in airports for the practicalities.
Connecting onward from Union Station
Travellers heading further into Colorado or onward by long-distance rail can connect at Union Station to Amtrak's California Zephyr, which runs west through the Rockies to Glenwood Springs and Grand Junction, and east to Chicago — a genuinely scenic long-distance option, if a slow one, for onward travel. Union Station is also the starting point for several regional bus and shuttle services heading up into the mountain resort towns.
Luggage, timing and first-timer tips
DEN's terminal layout means a reasonable walk between your gate and the train station regardless of which concourse you land at — build a little extra time into a tight connection, particularly if you're carrying a lot of luggage. RTD's MyRide card and the mobile app both make the fare payment straightforward without needing to work out a paper ticket system on arrival. If you're flying in very late at night, check current A Line operating hours, since it doesn't run right through the night — rideshare and taxis remain the fallback for the small hours.
Which option should you choose?
For almost anyone heading downtown, the A Line is the clear choice — fast, reliable and unaffected by the highway traffic that can make a car journey unpredictable over this distance. Rideshare or taxi makes sense for late arrivals, groups with heavy luggage, or a destination well away from Union Station. Renting a car is worth it if the mountains, not downtown Denver, are your actual destination.
If you're continuing into the mountains or across the state by road, our driving guide above covers the essentials, and for the wider rail picture see the USA by train. For advice on a tight onward flight connection through a hub this size, see minimum connection times explained.
Frequently asked questions
How do I get from Denver Airport to downtown?
The A Line commuter train runs directly from the airport terminal to Union Station in downtown Denver in around 35–40 minutes, and is generally the fastest and cheapest option.
How far is Denver Airport from the city?
DEN sits roughly 40 km east of downtown Denver, considerably further out than most major US airports, which is part of why the direct rail line matters so much for this transfer.
Is the A Line cheaper than a taxi from DEN?
Yes, generally by a wide margin — the fixed rail fare is well below a taxi or rideshare fare covering the same roughly 40 km distance.
Should I rent a car at Denver Airport?
Only if you're heading into the mountains or on a wider Colorado road trip — for the transfer into downtown Denver itself, the A Line is simpler and avoids city parking costs.
Sources and further reading:
- Airport transport information: Denver International Airport official site.
- A Line rail routes and fares: RTD (Regional Transportation District).