Colorado Area Codes
303, 720, 970 & 719
Need to call Denver, Aspen, or Colorado Springs? Connect instantly to any Colorado number. Whether it's a business in the Tech Center or a resort in the Rockies, make HD calls directly from your browser.
How to Call Colorado Step-by-Step
Calling Colorado follows the standard North American Numbering Plan (NANP).
Exit Code
Dial 00 (if in Europe) or your country's specific exit code.
(Or just use + on mobile/VoIP)
US Country Code
Dial 1. This is the country code for the United States, Canada, and parts of the Caribbean.
Area Code + Number
Dial the 3-digit Colorado area code (e.g., 303) followed by the 7-digit phone number.
Mandatory 10-Digit Dialing
Colorado has multiple "overlay" area codes (e.g., 303 and 720 both cover Denver). This means you must always dial the full 10 digits (Area Code + Phone Number), even for local calls within the same city.
Colorado Area Codes by City
Find the right area code for your destination in the Centennial State.
| City | Region | Code |
|---|---|---|
| Denver | Central / Metro | 303 / 720 |
| Colorado Springs | Southeast / Pikes Peak | 719 |
| Aurora | Denver Metro | 303 / 720 |
| Fort Collins | Northern Colorado | 970 |
| Boulder | Front Range | 303 / 720 |
| City | Region | Code |
|---|---|---|
| Aspen / Vail | Mountain Towns | 970 |
| Pueblo | Southern Colorado | 719 |
| Grand Junction | Western Slope | 970 |
| Durango | Southwest | 970 |
| Greeley | Northern Plains | 970 |
Why Use VoIP to
Call Colorado?
Calling US numbers from abroad using a traditional carrier can cost upwards of $0.034/minute. StartACall connects you via the internet for a fraction of the price, with crystal clear quality.
- Rates starting at $0.01/min to USA
- Call landlines and mobiles for the same price
- No roaming fees or contracts
- Perfect for business or travel
Statewide
Reach any number in Denver, Springs, or the remote Rockies.
No Roaming
Avoid expensive international carrier fees.
Secure
Encrypted calls ensure your business stays private.
Instant
No app download required. Just dial and talk.
Frequently Asked Questions
What is the difference between 303 and 720?
303 is the original area code for Denver and the surrounding metro area. 720 was added later as an 'overlay' code. Both cover the exact same geographic area, and calls between them are considered local, but require 10-digit dialing.
How do I call a 970 number?
Dial +1 followed by 970 and the 7-digit number. This area code covers Northern Colorado (Fort Collins), Western Colorado (Grand Junction), and the mountain resort towns (Aspen, Vail).
What time is it in Colorado?
Colorado is in the Mountain Time Zone (MST/MDT). It is generally 2 hours behind New York (EST) and 1 hour ahead of California (PST).
Can I call Colorado mobiles for free?
StartACall offers very cheap rates to US mobiles, often as low as $0.01/min. While not completely free, it is significantly cheaper than traditional international calling plans.
Ready to call Colorado?
Start making calls in seconds. No credit card required to sign up.