Phone customers in the 313 area code, which covers Detroit and several suburbs, will have to start including the area code when making local calls.
Here’s everything to know about when this change will take effect and why it’s happening.
Why is this new requirement being implemented?
The new change comes because they are getting low on numbers with the 313 area code for new customers, according to a release from the Michigan Public Service Commission.
Phone providers can start issuing a new 679 overlay area code to new customers in Metro Detroit on Friday, Nov. 7, 2025.
‘Permissive dialing’ period to adjust to change
A six-month “permissive dialing” period will start on April 7, 2025.
During this period, customers can make local calls with either seven or 10 digits.
When do I have to start 10-digit dialing?
Customers will need to start 10-digital dialing (area code and phone number) on Tuesday, Oct. 7, 2025.
If calls do not include all 10 digits, they will not be completed.
When a caller only uses seven digits, they might hear a recording that asks them to disconnect and redial using 10 digits.
When will 679 area start being used?
Telephone lines or services can be assigned the 679 area code on Nov. 7, 2025, but numbers with this area code will only be assigned once there are no new numbers with the 313 area code left.
Do I need to do anything before the switch?
Customers should make sure any software or equipment programmed to dial seven digits is reprogrammed:
- life-safety systems
- fax machines
- Internet dial-up numbers
- gates
- speed dialers
- mobile phone contact lists
- call forwarding settings
- voicemail services
- security equipment
- medical alert devices
Personal checks, advertising materials and pet ID tags are also some items the commission reminds residents to change.
People should keep in mind that the programming of alarms and security systems must be done between April 7 and Oct. 7.
Facts to know about the 679 area code
Here’s a list of facts to know about the addition of the 679 area code from the Michigan Public Service Commission:
- Your current telephone number, including the current 313 area code, will not change.
- You will need to dial the area code and telephone number for all local calls, including calls within the same area code.
- You will continue to dial 1 plus the area code and telephone number for all long-distance calls.
- What is a local call now will remain a local call.
- The price of a call, coverage area, or other rates and services will not change due to the overlay.
- You can still dial just three digits to reach 911 and 988. You can also dial three digits to reach 211, 311, 511, and 811 where available.
For more information, residents should contact their phone providers or visit the MPSC website.
