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AREA CODE · ILLINOIS

Area code 331

Area code 331 covers Aurora, Illinois. Map, time zone, overlays, carriers, the full list of prefixes and how to dial it.

State: Illinois Major City: Aurora Central Time (CT) Overlay: 331/630
01 / WHERE IT IS

Where is area code 331?

Area code 331 is assigned to Aurora and the surrounding region in Illinois. Calls to numbers that start with 331 are routed to this area.

Area code 331 shares its territory with 630. Because it is an overlay, local calls require dialing all 10 digits.

Counties covered

DuPage CountyKane CountyCook CountyKendall County

Line types

  • Mobile 45.7%
  • Landline 54.3%
02 / MAP

Area code 331 on the map

The shaded area joins the code’s numbering centers; the marker shows its main city.

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© OpenStreetMap contributors

03 / LOCAL TIME

Current time in Aurora

This area code is in the Central Time (CT) time zone.

Local timeAurora, IL--:--:--

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America/ChicagoLive
04 / HOW TO DIAL

How to call Aurora

WITHIN THE US331 XXX XXXX

Always 10 digits — landline, mobile or VoIP. Local, long distance or a different state: the format is always the same. You do not need to dial the 1 first.

FROM ABROAD+1 331 XXX XXXX

Exit codes: 00 Europe/Mexico · 011 Canada · 010 Japan · + universal

WHATSAPP / IMESSAGE+1 331 XXX XXXX

Always save the number in international format so messaging apps recognize it correctly:

Call typeTraditional landlineMobile / VoIP
Local (same area code)10 digits10 digits
US long distance1 + 10 digits10 digits
Emergency911911
🌐Universal+1 331 555 0123
🇪🇸🇲🇽Spain / Mexico00 1 331 555 0123
🇦🇺Australia0011 1 331 555 0123
🇯🇵Japan010 1 331 555 0123
HAVE THE FULL NUMBER?

Learn more about that number.

Check the line type and the carrier the number block was originally assigned to.

10 digits to see the carrier and line type of the number

05 / CARRIERS

Carriers in area code 331

Share of the number blocks by carrier and line type.

Landline

Sinch
32%
Fractel
15%
Bandwidth
9%
CoreTel Communications
8%
AT&T
6%
Others
31%

Mobile

T-MOBILE USA
38%
Verizon Wireless
32%
AT&T Mobility
25%
Sinch
5%
Boost Mobile
1%

Carrier shown is the original assignment of each number block and may differ today because of number portability.

06 / PREFIXES

Complete list of prefixes for area code 331

221 number blocks (NXX) assigned in this area code.

PrefixTypeCityCarrier
(331) 200 Mobile Bartlett T-MOBILE USAT-MOBILE USA, INC.
(331) 201 Mobile Downers Grove Verizon WirelessCELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL
(331) 202 Landline Elmhurst Metro by T-MobileMETROPCS, INC.
(331) 203 Mobile Aurora T-MOBILE USAT-MOBILE USA, INC.
(331) 204 Landline Naperville SinchONVOY, LLC
(331) 205 Mobile Aurora T-MOBILE USAT-MOBILE USA, INC.
(331) 206 Mobile Aurora T-MOBILE USAT-MOBILE USA, INC.
(331) 207 Landline Yorkville Lumen TechnologiesLEVEL 3 COMMUNICATIONS, LLC - IL
(331) 208 Mobile Aurora T-MOBILE USAT-MOBILE USA, INC.
(331) 209 Landline Elmhurst Lumen TechnologiesLEVEL 3 COMMUNICATIONS, LLC - IL

Showing 10 of 221 prefixes

07 / FAQ

Frequently asked questions about area code 331

Where is area code 331 used?
Area code 331 serves Aurora and the surrounding area in Illinois, including DuPage County, Kane County, Cook County, Kendall County.
What city is area code 331 from?
The main city of area code 331 is Aurora, IL.
What time zone is area code 331 in?
Area code 331 is in the Central Time (CT) time zone (America/Chicago).
Is 331 an overlay area code?
Yes. It shares its territory with 630. In an overlay, every call requires dialing all 10 digits.
How do I call a number with area code 331 from the United States?
Dial the 10 digits: 331 + 7-digit number. For some long-distance calls from a landline you may need to add a 1 first.
How do I call a 331 number from another country?
Dial your country's exit code (or +), then 1, then 331 and the seven-digit number. From a mobile you can use +1 331 XXX XXXX.
Which carriers use area code 331?
Most landline blocks belong to Sinch and most mobile blocks to T-MOBILE USA. The carrier shown is the original assignment and may differ today because of number portability.
Is area code 331 for landlines, mobiles or both?
Both. About 54.3% of the number blocks are landline, 45.7% mobile.
How do I save a 331 number in WhatsApp or my phone?
Save it in international format: +1 331 XXX XXXX. That way WhatsApp, iMessage and Telegram recognize it from any country.
Is it safe to answer calls from area code 331?
The area code only shows the region a number was assigned to; it does not tell you who is calling. Scammers can fake any area code, so do not share personal or banking information with unknown callers, and let unknown numbers go to voicemail.
KEEP EXPLORING

Nearby area codes

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Other area codes in Illinois

217 · Springfield224 · Arlington Heights309 · Peoria312 · Chicago447 · Danville464 · Tinley Park618 · Collinsville630 · La Grange708 · La Grange730 · Centralia773 · Chicago779 · Rockford815 · Rockford847 · Northbrook872 · Chicago

View all Illinois area codes →