Area code 520

Area code 520 is a telephone area code in the North American Numbering Plan (NANP) for the U.S. state of Arizona. The numbering plan area comprises Tucson and most of the southeastern part of the state.

Area code 520 was created in a split of area code 602 on March 19, 1995. Previously, 602 had been the sole area code for the entire state of Arizona since the introduction of area codes in 1947. Arizona's rapid growth in demand for telecommunication services during the second half of the 20th century, and the proliferation of mobile and data communication services in the 1990s required additional numbering resources. The numbering plan area originally comprised all of the state outside the Phoenix metropolitan area, but areas outside of southeastern Arizona were split again in 2001 to form area code 928 in 2001.