Chattanooga, TN Area Codes

Area codes serving Chattanooga

Chattanooga sits in Tennessee, part of the South region and the Central Time zone. Its numbers are spread across an overlay of 2 codes that all cover the same ground: 423, 729.

The original code is 423 (in service since 1995). As the area ran low on numbers, regulators added overlay codes on top instead of splitting the city, so longtime residents kept their numbers while new lines received a newer code.

Code	Area served	In service
423	Eastern Tennessee outside Knoxville, including Chattanooga and the Tri-Cities	September 11, 1995
729	Eastern Tennessee outside Knoxville, including Chattanooga and the Tri-Cities	September 5, 2025

Nearby cities sharing these area codes

• Johnson City
• Kingsport
• Cleveland
• Bristol
• Morristown
• Greeneville
• Elizabethton
• East Ridge
• Athens
• Red Bank
• Dayton
• Collegedale
• Rogersville

How to pick an area code for a new number

When you activate a new line in Chattanooga, the carrier assigns whichever code has numbers available — you usually can't choose. If a specific code matters to you (for example the prestige of 423), ask the carrier whether any blocks remain, or request a number transfer. All codes here dial identically and cost the same.

Dialing in Chattanooga

Because Chattanooga is an overlay area, 10-digit dialing is mandatory: always dial the area code plus the seven-digit number, even for a neighbor. See 10-digit dialing and overlay area codes for the background. For every code in Tennessee, visit the Tennessee area codes page.