NPA-NXX - 623-399

This is the 623-399 subcode (NPA-NXX) prefix page. Follow a prefix to find the number you are looking for. We divide our pages up to make them more user friendly to navigate!

1. Area Codes
2. 623
3. 623-399

The 623-399 subcode mainly covers Phoenix in Maricopa county. But other numbers maybe included as well.

We have a database of information derived from the public phone records of Arizona state. Many of the numbers in this subcode are Cellular (Dedicated) registered to T-mobile. We hear they employ a large number of people in the Arizona office.
Recently there have been an increase in reported calls, we've had over 3817117 comments across our systems for the 623-399 subcode.