With new telephone numbers in high demand, the Tennessee Public Utility Commission approved the addition of the new 729 area code to the existing 423 area code region, which covers two non-contiguous regions in eastern Tennessee, serving communities such as Bristol, Chattanooga, Johnson City and Kingsport, as well as many other smaller communities.
This process is known as an area code overlay. The overlay does not require customers to change their existing area code but will require dialing the area code and the 7-digit telephone number to complete local calls.
All customers with the 423 area code should prepare for 10-digit dialing and the introduction of the new 729 area code.
Starting August 5, 2024, a permissive dialing period began to give customers adequate time to adjust to including the area code when they make a local call. During this permissive dialing period, local calls can be made with either 7 or 10 digits.
Starting August 5, 2025, all local calls made within the 423 area code must be dialed using 10 digits (area code + the 7-digit telephone number). On and after this date, calls using just 7 digits will not be completed, and will be routed to an announcement.
Starting September 5, 2025, new telephone lines or services may be assigned numbers from the new 729 area code. The new 729 area code will co-exist everywhere in this region with the 423 area code. Anyone receiving a 729 number will be required to dial 10 digits as well.
The key facts to know about the upcoming 423/729 area code overlay are:
- Current telephone numbers, including current area code, will not change.
- Dial the area code + telephone number for all local calls, including calls within the same area code.
- Continue to dial 1 + area code + telephone number for long distance calls.
- What is a local call now will remain a local call.
- The price of a call, coverage area, or other rates and services will not change due to the overlay.
- You can still dial just three digits to reach 911 and 988, as well as 211, 311, 411, 511, 611, 711 and 811 where available.
To prepare for the new dialing procedure:
- Identify your telephone number as a 10-digit number and include the area code when giving the number to friends, family, business associates and customers, etc.
- Ensure all services, automatic dialing equipment, or other types of equipment that are programmed to dial a 7-digit number are reprogrammed to include the area code and to recognize the new 729 area code as a valid area code. Some examples include life-safety systems and medical monitoring devices, fire or burglar alarm and security systems or gates, cordless and mobile phone contact lists, fax machines, Internet dial-up numbers, ankle monitors, speed dialers, call forwarding settings, voicemail services, and other similar functions. Many systems operate on 10-digit dialing by default, but some older equipment may still use 7 digits. Please contact your medical alert or security provider if you are not sure whether your equipment needs to be reprogrammed to accommodate the upcoming change to 10-digit local dialing. Any needed reprogramming of such alarm and home security equipment must be done between August 5, 2024, and August 5, 2025.
- Update websites, personal and business stationery and checks, advertising materials, personal and pet ID tags, and other such items to ensure the area code is included.
For additional information, please visit the Tennessee Public Utility Commission website at www.tn.gov/tpuc/news.html or contact your local telephone service provider.