One NZ said data usage from its customers was 23 per cent higher than Christmas and Boxing Day last year.
It said this year 2519 TB of data went across its mobile network compared to 2054 TB last year. One terabyte is equal to 1000 gigabytes.
One NZ said that was equivalent to Kiwis streaming 1,679,249 hours of video in just two days.
The most popular times to go online were between 8pm and 9pm on both Christmas and Boxing Day, with peaks of 79 TB and 86 TB of data used respectively.
"This year we have added capacity across our end-to-end mobile network to support an approximately 30 per cent increase in overall projected data usage," said One NZ head of network services Sharina Nisha.
"We've done a heap lot of work preparing for skyrocketing data demand over summer and we're confident our network can cope with all those Christmas family video calls and New Year Eve selfies."
In the past 12 months One NZ has built 80 new mobile sites, 40 new small cells and upgraded a further 270 sites to keep people connected.
Over the festive season it had also deployed 16 'cellsite-on-wheels' (COWs) to areas where extra demand was expected such as events and holiday towns.
"Over the summer we'll be deploying our COWs at events like Rhythm and Vines, Rhythm and Alps, Northern Base, One Love, Festival One, SPLORE, Big Gay Out and one at Hagley Park to cover everything happening there," said Nisha.
"We've also sent COWs to Whangamatā and Mangawhai to add a bit of capacity at those locations."
Nisha said the telco was also looking to maximise coverage at other busy spots during the holidays, including the nation's shopping malls and along traffic routes heading out of the main centres.
Meanwhile Spark customers used over 2783 TB of data across Christmas Day and Boxing Day.
Spark said over 6.4 million mobile calls were also made and 712,000 text messages were sent.
Spark Network Delivery Lead Michael Molony said Spark's network team had been working throughout the year to bring 5G to more parts of the country, and to upgrade 4G and 5G capacity on existing cell sites.
Molony said Spark would also deploy almost 50 additional temporary cell sites into summer hotspots to help ensure customers had "great connectivity".
"We invest ~$100 million annually in our networks to increase capacity and coverage around New Zealand, so our customers can capture and share their experiences, stream until their heart's content and keep in contact with loved ones throughout the summer holiday period," he said.
From December 18, 2022 to December 18, 2023 Spark customers used almost eight billion voice minutes, sent over four billion text messages, and used around 440 billion megabytes of data.
By Krystal Gibbens
