Many East Tennesseans will soon have to adapt to dialing 10 digits for local calls, as the area gets a new area code.
The Tennessee Public Utility Commission announced the new 729 code in 2023, anticipating running out of 423 numbers sometime in 2025.
Numbers with the new 729 code can start being issued Sept. 5, according to the commission, but likely won’t actually be assigned until sometime next year.
(READ MORE: New area code, 10-digit dialing coming to East Tennessee)
Projections now show all available 423 numbers should be used up sometime by the third quarter of 2026, said Grace Marek, a financial regulatory analyst with the commission.
“It’s an indication of growth in the area,” Marek said by phone. “That’s super important.”
Initially, 10-digit dialing was set to begin in February, but it was pushed back after damage from Hurricane Helene delayed necessary updates to communications infrastructure, Marek said.
“Emergency alarm systems is a big one,” Marek said.
What areas will be covered by the new area code?
The 729 area code will serve the same area as 423.
That covers the Chattanooga area, southeastern Tennessee and parts of northeastern Tennessee outside of Knoxville, including Bristol, Kingsport and Johnson City.
The 423 area code split from 615 in 1995, according to the commission.
The new 729 code is projected to meet 34 years of demand for new phone numbers, commission documents show.
When do I have to start dialing 10 digits?
Tuesday.
Any local calls, even between 423 numbers, must be made with 10 digits or they will be routed to an announcement about the change, according to the commission.
For billing and service purposes, those calls are still considered local calls.
Will anything happen to my 423 number?
No.
Do I have to do anything else to prepare?
The commission recommends checking a few things before the change goes into effect.
1. Save your own number as a 10-digit number, so anyone you give it to has the right version.
2. Make sure any automated services, like alarm systems, medical monitors, voicemails or speed dials, have the 10-digit number programmed. This also applies to things like fax machines, ankle monitors, call forwarding or internet dial-up.
3. Update anything else that lists your number, like pet tags, business cards, checks, stationery or websites.
When will people start getting 729 numbers?
No 729 numbers can be assigned until all available 423 numbers are gone, Marek said, likely not until next summer or fall.
That’s based on projections from the North American Numbering Plan Administrator, which dictates numbering for the United States, its territories, Canada and some Caribbean countries.
“Of course, that is just a forecast,” Marek said. “So it does change every so often, depending on the amount of numbers requested from companies and consumers.”
Contact growth reporter Ellen Gerst at egerst@timesfreepress.com or 423-757-6319.