Spark New Zealand has announced it will switch off its 3G network by March 31, 2026.

The new retirement date of the Kiwi telco's 3G network is an extension to the originally planned shutdown this year.

Spark said it would shut down the network by the end of 2025 back in 2023.

The company, which first launched its 3G network in 2009, revealed that less than two percent of its entire network data traffic runs over 3G, while 3G voice calls have declined by 85 percent since 2019.

As part of its 3G retirement, Spark has upgraded its 4G and 5G networks. Since 2023, the carrier said it has built more than 70 new 4G mobile sites and upgraded more than 600 others.

The carrier also noted that all 3G-only cell towers will be upgraded to modernized 4G and 5G technology, with the majority of these upgrades already completed.

At present, Spark claims its 4G and 5G networks collectively cover more than 99 percent of the country's population.

“We’ve been preparing for this change for a while now, both at a network level, but also with our customers – ensuring they have access to the right information to support them during this transition," said Spark’s network and operations director, Renee Mateparae.

To support the migration away from 3G, Spark said it has invested in a nationwide joint industry awareness campaign to help customers understand how to move to 4G.

Mateparae added: “Our 4G network already reaches more New Zealanders than 3G, and we’re upgrading all 3G-only towers to 4G and 5G technology, as well as building more towers and boosting capacity where we need to. 

“That said, we do recognize that at the edges of the network, the 4G coverage might differ slightly compared to 3G, due to the nature of how these technologies work. So, we’ll be keeping a close eye on those areas and working with anyone affected to support them with connectivity options, which could include WiFi calling, external antennas, or satellite – which will be available to Spark customers in early 2026."

Rival telco One New Zealand has previously said it will switch off its 2G and 3G networks by the end of next year, while another domestic rival 2degrees has plans to retire the network this year.