The 520 area code covers Tucson, Sierra Vista and 22 more places in Arizona.
Area code 520 is in Arizona, on Mountain Time, no daylight saving. In the 520 area, phone numbers are given out most in Pima County, then Cochise and Pinal counties. It has been in service since March 19, 1995.
- Where
- 8 counties in Arizona, mostly Pima County, Cochise County and Pinal County
- Time zone
- Mountain Time, no daylight saving
- In service since
- March 19, 1995
- Shares its area with
- No other area code
- Prefixes in use
- 694
- How to dial
- Local calls need all 10 digits: 520-555-0142.
Find out who called you from a 520 number.
Enter the full 10-digit number to see who it is listed to and the city and state on the listing. It is the same free check as our who called me lookup. To see only the caller ID name on the number, use our free CNAM lookup. To see whether it is a mobile, a landline or a VoIP line, use our free VoIP checker. To see which carrier a (520) number is on today, use our free carrier lookup.
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Tucson holds 57% of the phone prefixes in area code 520.
A prefix is the three digits after the area code, and NANPA assigns each one to a town. Counting the 694 prefixes in use shows where 520 numbers are actually given out.
- Tucson399 prefixes, 57%
- Sierra Vista70 prefixes, 10%
- Casa Grande67 prefixes, 10%
- Nogales31 prefixes, 4%
- Willcox18 prefixes, 3%
- Benson12 prefixes, 2%
- Hayden9 prefixes, 1%
- Bisbee9 prefixes, 1%
Also served: Douglas, San Manuel, Tombstone and Superior and 12 smaller places.
Qwest (Lumen) holds the most phone number prefixes in area code 520: 200 of 694.
NANPA, which runs the North American numbering plan, assigns each prefix (the three digits after the area code) to one carrier. Here is how the 694 prefixes in use in 520 divide between carriers; holders this page does not name are grouped as other carriers.
| Carrier | Prefixes | Share |
|---|---|---|
| Qwest (Lumen)Lumen's landline company | 200 | 29% |
| T-MobileMobile network | 84 | 12% |
| AT&T MobilityMobile network | 53 | 8% |
| Level 3 (Lumen)Lumen's business and wholesale network | 29 | 4% |
| BandwidthSupplies numbers to VoIP and app-based phone services | 17 | 2% |
| Teleport (AT&T)AT&T's business phone network | 14 | 2% |
| 42 other carriers | 297 | 43% |
70% of these prefixes are pooled, which means the blocks of 1,000 numbers inside them can belong to other carriers. Any number can also have been moved to another carrier since, so this shows who holds the prefixes, not who serves a given number.
Want the carrier of one exact number? Our free carrier lookup checks it, because numbers move between carriers.
Source: NANPA central office code assignments, October 1, 2026.
520 has been split once since 1995.
1995
520 starts on March 19, 1995, split off from 602.
2001
On June 23, 2001, 928 splits off and takes part of the 520 area.
A 520 number on your screen can still be a scam, because caller ID is easy to fake.
- Let an unknown call go to voicemail. A real caller leaves a message; a robocaller usually does not.
- Look the number up with the box above before you call back, because calling back tells a robocaller your line is live.
- Hang up on anyone who wants gift cards, crypto or a wire transfer, or asks you to read out a code that was just texted to you.
- Report unwanted robocalls at reportfraud.ftc.gov, or paste a suspicious message into our free scam checker.
The area codes closest to 520 are 928, 602 and 702.
This list measures the distance between the centres of each area, across state lines, and shows codes that share one area together.
These are the questions people ask most about area code 520.
Where is area code 520?
520 covers Tucson, Sierra Vista, Casa Grande and Nogales and 20 more places in Arizona. In the 520 area, phone numbers are given out most in Pima County, then Cochise and Pinal counties.
What state is area code 520 in?
Arizona. 520 is an Arizona area code on Mountain Time, no daylight saving.
What cities use area code 520?
The places holding the most 520 prefixes are Tucson, Sierra Vista, Casa Grande, Nogales, Willcox, Benson, Hayden and Bisbee, out of 24 places in all. The count comes from NANPA's prefix assignments as of October 1, 2026.
Which phone company owns area code 520?
No single phone company owns 520. NANPA's records show Qwest (Lumen) holds the most 520 prefixes, 200 of 694, followed by T-Mobile and AT&T Mobility. Numbers move between carriers, so check one exact number with a carrier lookup.
What time zone is area code 520 in?
520 is on Mountain Time, no daylight saving.
When did area code 520 start?
520 went into service on March 19, 1995, when it was split off from 602.
How do I dial a 520 number?
Local calls need all 10 digits: 520-555-0142.
Is 520 a toll-free number?
No. 520 is a regular area code for Tucson and Sierra Vista in Arizona, not a toll-free one. The toll-free codes in North America are 800, 833, 844, 855, 866, 877 and 888.
What area codes are near 520?
The closest are 928 (Yuma, Arizona), 602/480/623 (Phoenix, Arizona) and 702/725 (Las Vegas, Nevada), measured between the centres of each area.
Who called me from a 520 number?
Enter the full 10-digit number in the lookup above. It returns the listed owner where there is a public record, where the number is registered, and whether it is a mobile, a landline or a VoIP line.
Is area code 520 a scam?
520 is a real Arizona area code, so the code itself is not a warning sign. Scam callers fake local-looking numbers on purpose, so judge the call by what the caller asks for, and look the number up before calling back.
Put this lookup on your site: our free area code widget takes two lines of code and shows any US area code's state, time zone and local time.
Source: NANPA, the North American Numbering Plan Administrator: its area code database and prefix assignments, as of October 1, 2026.