State
Area Code 331
Aurora, Naperville, Downers Grove, Illinois
Local time now
…
Time zone
Central
Main cities
Aurora, Naperville, Downers Grove, St. Charles, Lombard, Elmhurst
Overlays
In service since
2007
When you can make sales calls to 331 numbers
| Monday – Friday | 8 AM – 9 PM |
| Saturday | 8 AM – 9 PM |
| Sunday | 8 AM – 9 PM |
In the called person's local time. Guidance, not legal advice.
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Other area codes in Illinois
Questions about area code 331
- Where is area code 331?
- Area code 331 is in Illinois, covering Aurora, Naperville, Downers Grove, St. Charles.
- What time zone is area code 331?
- Central time.
- When can telemarketers call a 331 number?
- Federal rules allow sales calls from 8 AM to 9 PM local time, and Illinois has stricter hours shown on this page.
- Is 331 a toll-free number?
- No. 331 is a regular area code for Illinois. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.