Chattanooga, Tennessee · EST/EDT (UTC-5) · United States
Chattanooga, Johnson City, Kingsport — eastern Tennessee
Scenic City. First city in US to offer city-wide gigabit internet.
Dial 1 + 423 + 7-digit number for calls from outside the area. Local calls within the same area code may use 7-digit dialing where available.
From outside United States: dial your country's exit code + 1 + 423 + number. From most countries, the format is +1-423-XXX-XXXX.
Area code 423 is in EST/EDT (UTC-5). Business hours are typically 9:00 AM – 5:00 PM local time. Remember that clocks shift during DST (March–November).
While (423) is a legitimate area code, scammers can spoof any number. Never share personal info with unknown callers. Verify by calling the organization directly.
Area code data sourced from NANPA. Timezone data from IANA Time Zone Database. Last updated March 2026.