One New Zealand has completed the shutdown of its 2G and 3G networks.

The telco confirmed the retirement of its legacy networks today (March 23), after kicking off the shutdown in January in Dunedin.

The telco previously planned to retire its 3G service in March 2025, after delaying it from an initial shutdown date of August 2024.

One NZ will use the 3G radio spectrum to boost its 4G and 5G services.

“By switching off the old technology and re-using the radio spectrum on 4G and 5G, we can boost speeds, increase capacity, and make sure our network is ready to support New Zealanders with what’s next," said Kieran Byrne, chief technology officer at One NZ.

To support the carrier's 4G and 5G focus, Byrne noted that the company has invested NZ$100 million (US$58m) in the past 12 months.

“Our teams at One NZ have been contacting customers for over two years to make sure everyone had plenty of notice and, wherever possible, nobody was left behind," he added. "We know that there are a very small number of customers who, for whatever reason, will not have made the switch in time."

Byrne warned any customers still using 2G and 3G-ready handsets to upgrade their mobile devices.

Rival telco 2degrees completed its 3G network shutdown last month, while Spark is on course to retire its 3G network later this month.