The more densely populated area of the state of Arizona with the city of Phoenix and its surrounding large and small communities is currently divided into 3 Numbering Plan Areas as follows:
- NPA 480, serving parts of Phoenix and other cities and towns including Chandler, Mesa, Scottsdale or Tempe
- NPA 602 serving mostly the city of Phoenix
- NPA 623 covering the city of Glendale and other communities west of Phoenix including Avondale, Buckeye or Tolleson
From September 12, 2023 the 3 area codes mentioned above will overlay or will each cover the whole geographic area currently served by the 3 NPAs separately. This measure is to be implemented as the relief method for the 480 NPA.
With the implementation of the new overlay complex 480/602/623 no longer will subscribers to 602 and 623 telephone numbers be able to dial 7 digits when calling locally (10 digit dialing is already in use for area code 480).
- February 11, 2023 – local calls originating in NPAs 602 and 623 may be dialed using both 7 and 10 digits (permissive dialing)
- August 12, 2023 – mandatory 10 digit dialing begins for the entire area
- September 12, 2023 – boundary elimination date and birth of the new overlay complex 480/602/623
See official NANPA document announcing the change with map of the area (PDF document)