Denver Does 10-Digit Dialing 100 Real Estate Tips in 100 Days (Day 44) Beep! Beep! Beep! If you hear that sound chances are you come from a different area! A few years back, Metro Denver adapted 10 digit dialing. What that means is when calling inside the Metro area; all calls require 10 digits, starting with 720 or 303. Although local Metro Denver calls require 10 digits, it is not necessary to dial (1). The reason was the number of required telephone numbers to service the growing Denver area. There was a choice between cutting the area in half, or "overlaying" another area code. The choice was the overlay, so all local calls require 10 digits. So if you are new to the area, it won't take you too long before you get used to dialing those 3 extra digits. If you don't the friendly beep, beep, beep will remind you and soon it will become a habit! Welcome to Denver, newcomer!