When traveling to DIA, you need to determine whether or not you need a car. Downtown Denver has adequate public transportation, cab drivers, and light rail. However the suburbs require a bankroll and patience for taxis, or a rental car. The best method is to travel in a group, rent a car, and designate a sober driver for the ultimate access to the city, and state. Buyer Beware, DUI is no Joke up here!
If you are going to Downtown Denver, riding the bus, hotel buses, and other options keep you from paying for the $100 cab ride. If you are going somewhere else in the city, that $100 could buy you a few days of a rental car. The RTD system is robust, safe, and you stop twice en route to downtown Denver.
Each of the major car rental places operates buses that pick you up on level five, just outside of the doors from baggage claim. The rental offices are located in the center of the airport on level 5, on either side of the exit from the concourse trains. We suggest you deboard your plane, use the bathroom near your gate, and then board the trains toward the main terminal. Next, exit the train from the concourses, and find your rental car location. Go through the paperwork here prior to claiming your bags. Then proceed directly to the car rental bus. This order of operation avoids backtracking, carrying your bags to the rental office, and streamlines the process.
Only the really well off plan to pay for a $100 cab ride to the airport. The locals know how to avoid it, but support the activity as it pays for the airport. This knowledge will not only save you time but also keep some coin in your wallet.