Max Reinhart, The Detroit News
State officials said they’ve almost exhausted the 313 area code and Detroiters will have to start dialing the full 10-digit phone number, even for local calls, starting in October.
Beginning Oct. 7, all local calls made within the 313 area code footprint must use all 10 digits. Calls placed with only seven digits won’t be completed and callers will receive a message asking them to disconnect and try their call again, the Michigan Public Service Commission (MPSC) said in a press release Monday.
Telephone service providers can begin issuing an “overlay area code,” 679, to new phone customers in the 313 area, which includes Detroit and several of its closest suburbs, starting Nov. 7. This means callers must dial all 10-digits in order for their call to go through, MSPS said.
To give customers time to get used to the change, a six-month “permissive dialing” period will begin April 7. From then until Oct. 7, local calls can be made by dialing either the seven- or 10-digit number.
New phone lines or services will only be assigned numbers using the new 679 area code after all 313 numbers are exhausted, which isn’t projected to happen until late in 2027. However, MPSC said that timing is subject to change depending on demand, and new lines could be assigned the 679 area code as early as Nov. 7, 2025.
Customers who currently have a number with a 313 area code will be able to keep their existing phone number, MPSC said.
All calls currently considered local will remain so, MPSC said, and callers will continue to dial 1, plus the area code, for long-distance calls.
The price of a call, coverage area or other rates and services will not change due to the overlay, the commission said.
Special three-digit numbers like 911 and 988 will be unchanged.
Phone customers are encouraged to identify their telephone number as a 10-digit number and include the area code when giving the number to friends, family, business associates, customers and others.
Callers should also ensure that all services, automatic dialing equipment, applications, software or other types of equipment are reprogrammed to dial 10 digits if they are currently programmed to dial seven digits and to recognize the new 679 area code as a valid area code. Examples include life-safety systems, fax machines, Internet dial-up numbers, gates, speed dialers, mobile phone contact lists, call forwarding settings and voicemail services.
“Be sure to check your business stationery, advertising materials, personal checks, and your personal or pet ID tags to ensure the area code is included in your telephone number,” MPSC said.
Important safety and security equipment like medical alert devices, alarms and security systems may also need to be reprogrammed, between April 7 and Oct. 7, to use 10-digit dialing. Many systems use 10 digits by default, but older equipment may not, the state said. Anyone unsure about this should contact the service provider.