Getting in

• Denver International Airport: Take RTD’s direct AB airport bus to Boulder rather than a $100-plus taxi or rideshare. It runs to Boulder Transit Center and key Boulder stops in roughly 60–75 minutes; budget about $10 for the airport fare. A taxi’s published flat fare is about $115 one way, so it only makes sense for a full carload or a very late arrival.
• Denver Union Station (Amtrak and downtown Denver rail hub): Use RTD’s Flatiron Flyer (FF1) along US 36 to Boulder Transit Center. It is the sensible Denver–Boulder link: roughly 45–60 minutes depending on traffic, with frequent service and a low local/transit fare. Do not pay for an Amtrak throughway connection if the Flyer is running; it is generally more frequent and cheaper.