North American Numbers Source-cited · ownership disclosed
Area code
520
In service
United States · since 1995

Tucson

Created in 1995 as the first split from statewide 602, serving southern/southeastern Arizona including Tucson; a standalone code with no overlay.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Tucson
Type
geographic
Status
in service
In service since
1995
Projected exhaust
2031 Q3

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 520 is

Southeastern Arizona: Cochise, Pima, Pinal, and Santa Cruz counties (and vicinity)..

Communities served wholly or partly by 520:

TucsonSierra VistaNogalesCasa GrandeBenson

Wikipedia lists 70+ municipalities; a county list that includes "Maricopa" likely refers to the city of Maricopa (in Pinal County) rather than Maricopa County (UNVERIFIED).

B · Relationships

How it relates to other codes

The codes 520 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Split from · 1995 602 Phoenix Split from the original statewide 602.
Spawned · 2001 928 Flagstaff / Yuma / northern Arizona Northern/western Arizona split off from 520.
What's changing. Standalone (no overlay).
C · History

How 520 got here

1995-03-19
Area code 520 went into service (permissive dialing) via split from 602.
Source: Wikipedia
1995-10-22
Mandatory dialing began in rural areas.
Source: Wikipedia
1996-12-31
Mandatory dialing in Tucson.
Source: Wikipedia
2001
Area code 928 split off, removing northern/western Arizona from 520.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
709
Prefixes available
91
Thousands-blocks assigned
3,811

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 520 with another code →
Sources
Wikipedia ↗
Area code 520
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.