Starting August 5, residents in Chattanooga and across the 423 area code will be required to use 10-digit dialing for all local calls—even when calling within the same area code. The change is part of a statewide plan to introduce a new area code, 729, to accommodate growing demand for new phone numbers.
The Tennessee Public Utility Commission has approved the 729 area code overlay, which will serve the same geographic region as the existing 423 code. This includes not only Chattanooga but also Bristol, Kingsport, Johnson City, and many surrounding communities in eastern Tennessee.
While current 423 phone numbers will remain the same, the overlay means local calls must now include the area code to go through. Calls dialed using only seven digits after August 5 will not be completed and will play a recorded message instructing the caller to redial using 10 digits.
Beginning September 5, new phone numbers in the region may be assigned the 729 area code. Both 423 and 729 numbers will operate side by side in the same region, and all users will follow the 10-digit dialing format.
What You Need to Know:
Your existing phone number and area code will not change.
Local calls must be dialed as area code + 7-digit number.
Long-distance calls still require 1 + area code + number.
Rates, coverage areas, and service terms will remain the same.
Three-digit numbers such as 911, 988, 211, and 411 can still be dialed as usual.
How to Prepare:
Reprogram contact lists, security systems, fax machines, and medical alert devices to use 10-digit dialing.
Ensure business materials, websites, and personal records include the full 10-digit number.
Contact your service provider or device manufacturer if you are unsure whether your equipment needs updating.
The change is being made to ensure there are enough phone numbers available as the region continues to grow. For more details, visit the Tennessee Public Utility Commission’s website.
