Area codes 602, 480, and 623

Area codes in Arizona and surrounding states, with the 480–602–623 overlay complex highlighted in red.

Inset of the metro Phoenix area, showing the boundaries of area codes 480, 602, and 623 from 1999 to 2023, with 602 serving the middle of the present 602 area flanked by 623 to the west and 480 to the east.

Area codes 602, 480, and 623 are telephone area codes in the North American Numbering Plan (NANP) for most of the Phoenix metropolitan area in the U.S. state of Arizona.

Area code 602 is the oldest area code in Arizona and was assigned in 1947 for the entire state. Under pressure from population growth and new telecommunications services, the numbering plan area (NPA) was reduced twice in five years in the 1990s. In 1995, the state outside metropolitan Phoenix was split off with area code 520. In 1999, a second split created two new area codes: 480 in the East Valley and 623 in the West Valley. Metro Phoenix continued to be a single rate center after the split, so that calls between the three area codes were generally local calls.

By the early 2020s, 480 and 602 were facing exhaustion within the decade, but 623 continued to have hundreds of unassigned central office codes and was not expected to exhaust for the foreseeable future. As a result, the Arizona Corporation Commission, which regulates public utilities, approved a plan in 2021 to reverse the 1999 split and convert 602, 480, and 623 into overlay codes for the entire Phoenix area in 2023. The creation of the three-code overlay complex made ten-digit dialing mandatory across the Valley; it was already required in 480.