Area Code 423: Cities, Coverage, and Key Information - area-code -

Frequently Asked Questions

Area code 423 covers two main areas in East Tennessee: the Tri-Cities region (Bristol, Johnson City, Kingsport, Greeneville, Morristown) and the Chattanooga and Cleveland area.
10-digit dialing (area code + 7-digit number) will be mandatory for all local calls within area code 423 starting February 5, 2025.
The split is due to telecommunication planning and population growth. Area code 865 (Knoxville) was carved out of the original 423 area in 1999.
Area code 729 will be overlaid on the existing 423 region starting in March 2025. Both area codes will serve the same geographic area.
Dial 1 + the 10-digit number (area code + 7-digit number) for long-distance calls.
The Tennessee Public Utility Commission (TPUC) oversees area code 423, regulates telecommunications providers, and approves area code changes and dialing procedures.
Update all contacts with the 423 area code, check automatic dialing devices and update website/business materials.
No, existing 423 numbers will not change. Area code 729 will be assigned to new phone lines and services.
Initially, you'll hear a reminder message. Eventually, the call won't go through.
No, long-distance rates will not change. Local calls will remain local calls.
Contact the Tennessee Public Utility Commission (TPUC) at (800) 342-8359 or (615) 741-2904.
Area code 423 was created in 1995 from area code 615, and 865 was later carved out of 423 in 1999.
Knoxville, TN uses area code 865.
The number 865 corresponds to "VOL" (Volunteers) on a telephone keypad, a nod to the University of Tennessee's sports teams.
Area code 423 covers parts of eastern Tennessee, including the Tri-Cities (Bristol, Johnson City, and Kingsport) in the northern section and Chattanooga and Cleveland in the southern section. These two sections are not geographically connected, creating a unique coverage pattern.
Currently, you can dial 7 digits for local 423 calls. However, 10-digit dialing (423 + the 7-digit number) will be mandatory starting February 5, 2025. This change prepares for the new 729 area code overlay.
The non-contiguous nature of area code 423 is due to telecommunication planning and population growth. Initially, 423 covered a larger area, but area code 865 (Knoxville) was split off in 1999, resulting in the current configuration.
10-digit dialing for all local calls within area code 423 becomes mandatory on February 5, 2025. This applies to calls within 423 and to the new 729 area code, which will be implemented in March 2025.
Area code 729 will overlay the existing 423 region starting in March 2025. Both area codes will serve the same geographic area, requiring 10-digit dialing for all local calls.
Add the 423 area code to all your contacts before the mandatory 10-digit dialing starts in February 2025. This simple step ensures smooth communication and avoids disruptions when making local calls.
Chattanooga, Tennessee is in area code 423. However, remember that 10-digit dialing will be required for local calls starting February 2025, due to the introduction of the new 729 area code overlay in the region.
The new 729 area code is being implemented due to the increasing demand for phone numbers in the 423 region. This demand is driven by population growth and the proliferation of communication devices.
No, your existing 423 phone number will not change. Area code 729 will be assigned to new phone lines and services, while existing 423 numbers remain the same.
The Tennessee Public Utility Commission (TPUC) regulates area code 423 and oversees telecommunications providers in the state. The TPUC approves area code changes and implements new dialing procedures, ensuring reliable service.
You can contact the TPUC by phone at (800) 342-8359 or (615) 741-2904, or visit their website (https://www.tn.gov/tpuc) for further information regarding area code changes and telecommunication services.
Initially, you'll likely hear a recorded message reminding you to include the area code. Eventually, as the transition completes, calls without the area code will simply not go through.
Yes, you can still dial 911 for emergencies, as well as other N11 codes like 988 (Suicide & Crisis Lifeline) and 211 (Community Information and Referral), where available. These numbers remain unaffected by the area code changes.
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