520 area code — Tucson, AZ geographic
If a call shows area code 520, the number was issued in the Tucson area — a code active since 1995, on Mountain time. Because of number portability and VoIP, the area code tells you where the number was issued, not where the caller is right now.
NANPA lists 692 active NXX prefixes in 520, assigned to 51 carriers. 485 of those prefixes are pooled — shared between carriers in thousands-number blocks. The code spans 37 rate centers (billing localities).
Official projections put exhaust at 3Q 2031 — relief planning typically starts years ahead.
Its parent code is 602, which it left in 1995. Later relief produced 928 (2001) from its territory.
The dialing plan is 10D for home-NPA local calls and 10D across codes.
Practical takeaway: the 520 label narrows geography to Arizona, the prefix narrows it to a locality, and neither authenticates a caller. Verification means calling back through a number you found yourself.
Largest localities in 520
| Locality (rate center) | Active prefixes | Also served by |
|---|---|---|
| Tucson | 398 | — |
| Sierra Vista | 70 | — |
| Casa Grande | 66 | — |
| Nogales | 31 | — |
| Willcox | 18 | — |
| Benson | 12 | — |
| Hayden | 9 | — |
| Bisbee | 9 | — |
| Douglas | 9 | — |
| San Manuel | 8 | — |
FAQ
Will 520 run out of numbers?
NANPA's current forecast projects exhaust in 3Q 2031, so a new overlay is likely to be planned.
Why am I getting spam calls from 520 numbers?
Scammers spoof recognizable area codes so calls look local or familiar. A displayed 520 number does not prove the call originated there — see our guide to spotting spoofed calls.
Where is a 520 number from?
520 is assigned to Tucson and surrounding areas of Arizona in the Mountain time zone. The three digits after the area code (the prefix) narrow it down to a rate center.