One NZ has kicked off its planned 3G shutdown from today (January 20).

The telco confirmed that the 3G network switch-off will be carried out in phases, beginning with the Dunedin region.

One NZ has been planning its 3G shutdown for several years, with a full switch-off planned by March 31, 2026.

The telco previously planned to retire the service last March, after delaying it from an initial shutdown date of August 2024.

The carrier will use the 3G radio spectrum to boost its 4G and 5G services.

“After years of preparation and customer communication, Dunedin will be the first city where we switch off 3G, starting tomorrow on Tuesday, 20 January,” said Kieran Byrne, chief technology officer, One NZ.

“Switching off 3G lets us deploy more of our radio spectrum into 4G and 5G, meaning faster speeds, better coverage, and a more reliable network for our customers,” said Byrne.

Last year, the carrier completed 258 mobile upgrades, including upgrading every one of its mobile sites across New Zealand with 4G technology, including a large portion with 5G.

The full phased shutdown has been detailed via One NZ's website.

Domestic rival 2degrees started its 3G switch-off last month, while Spark NZ extended its 3G shutdown date until March, and will also call time on the service on March 31, 2026.