Area code 423 covers Chattanooga and surrounding areas in Tennessee. It was activated in 1995 as an overlay of area code 615. Today it shares its territory with overlay code 729. For the full picture, see all Tennessee area codes.
| State | Tennessee |
|---|---|
| Primary city | Chattanooga |
| Cities also served | Chattanooga, Johnson City, Kingsport, Bristol, Cleveland, Morristown, Greeneville, Athens |
| Time zone | Eastern (UTC-5 / UTC-4 DST) |
| Year established | September 11, 1995 |
| Original 1947 NPA? | No |
| Parent code | 615 |
| Overlay codes | 729 |
| Currently in use? | Yes, actively assigned |
| Ten-digit dialing required? | Yes |
Cities Served by Area Code 423
Area code 423 serves East Tennessee — Chattanooga metropolitan area and the Tri-Cities region (Johnson City, Kingsport, Bristol), plus portions of Van Buren and Sequatchie counties, including the following cities and communities:
- Chattanooga
- Johnson City
- Kingsport
- Bristol
- Cleveland
- Morristown
- Greeneville
- Athens
Nearby area codes covering the same broader region include: 615, 629, 865, 901, 931.
How to Get a 423 Phone Number
There are three ways to get a phone number with the 423 area code, each suited to a different need:
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Browse 423 Numbers →- Buy from a premium-number specialist. Companies that hold curated inventories of specific area codes can sell you a 423 number directly, often with a one-time fee and ownership transferred to you (no recurring carrier fees). This is the option for picking a specific memorable number, or for getting an area code that most carriers won’t let you request. Browse our 423 inventory.
- Sign up with a VoIP carrier. Voice-over-IP services (such as Google Voice, OpenPhone, Grasshopper, and many others) can typically provision a 423 number on request, especially for active overlay codes. You won’t usually get to pick the specific number, but you’ll get a working line in the area code. This is the cheapest option for anyone who doesn’t need a particular number.
- Port an existing 423 number. If you already have a 423 phone number with another carrier, you can transfer it (port it) to a new service provider while keeping the number. This works for landlines, cell phones, and VoIP services, though landlines outside of Tennessee sometimes can’t accept inbound ports of 423 numbers due to 911 routing rules.
Looking for a 423 number? 212areacode.com offers premium 423 numbers for Chattanooga, Tennessee — choose your number, port it to any carrier in 3–5 business days, and pay a one-time fee with no monthly charges. Browse available 423 numbers →
Frequently Asked Questions
Is the 423 area code still in use?
Yes. 423 is actively assigned to new phone lines in East Tennessee — Chattanooga metropolitan area and the Tri-Cities region (Johnson City, Kingsport, Bristol), plus portions of Van Buren and Sequatchie counties.
What is the difference between 423 and 729?
Today they share the same geographic territory in Tennessee. New phone lines in the area may be assigned either code. The two codes work identically for calling, billing, and service.
What is the parent area code of 423?
Area code 423 is an overlay of 615. Both codes serve the same region of Tennessee.
Can I get a 423 number if I don't live in Tennessee?
Yes. Phone numbers are no longer tied to a physical address. With VoIP service or a number broker, you can hold a 423 number from anywhere in the world. The number routes to whatever device or carrier you specify.
Is 423 a scam area code?
No. 423 is a legitimate, active area code for East Tennessee — Chattanooga metropolitan area and the Tri-Cities region (Johnson City, Kingsport, Bristol), plus portions of Van Buren and Sequatchie counties. Like any area code, scammers occasionally spoof 423 caller IDs, but the code itself is heavily used by real Tennessee businesses, government offices, and residents.
What cities are in the 423 area code?
Major cities include Chattanooga, Johnson City, Kingsport, Bristol, Cleveland, Morristown, Greeneville, and Athens, covering roughly 28 counties across East Tennessee.
Does area code 423 have an overlay?
Yes. Area code 729 was approved as an all-service overlay on May 30, 2023. Permissive ten-digit dialing began August 5, 2024, and mandatory ten-digit dialing took effect August 5, 2025.
Why is area code 423 non-contiguous?
When area code 865 was carved out for Knoxville in 1999, it split 423 into two separate geographic sections — the Tri-Cities area in the northeast and the Chattanooga area in the southeast — making 423 one of the few non-contiguous area codes in the United States.
What time zone is the 423 area code in?
The 423 area code is primarily in the Eastern Time Zone (UTC-5 standard, UTC-4 daylight saving), though a small western portion of the numbering plan area touches the Central Time Zone.
