The UK operator's decision will also affect customers of mobile virtual network operators (MVNOs) operating on its network, such as Giffgaff, Tesco and Sky Mobile.

The announcement means that 2025 will mark the end of 3G in the UK. So far, VMO2 has lagged behind its competitors, and several other UK mobile operators have previously announced 3G phase-out timetables. VMO2 will also be the last telecommunications company in the UK to shut down its 3G network. Vodafone plans to completely phase out 3G technology in early 2024, and EE and Three will also shut down later in 2024.

Telecom operators are shutting down legacy legacy networks for a variety of reasons. On the one hand, it is to make better use of spectrum, because the new generation of mobile networks provides higher spectrum efficiency and network capacity. As demand for data-intensive applications grows, maximizing the use of available spectrum is key.

Another reason is to reduce energy consumption. According to VMO2, 3G accounts for 11% of the company's overall energy consumption, but the technology transmits less than 4% of the data. At the same time, 4G and 5G together account for 29% of energy consumption and 96% of the data transmitted. As a significant component of a telecommunications company's operating expenses, energy usage is an important consideration.

Reducing energy use also has an impact on carbon emissions. According to GSMA estimates, in a high-income country with a population of 80 million (the UK population is about 67 million), re-farming 3G spectrum can reduce emissions by an additional 3 million tons of carbon dioxide equivalent.

However, it is crucial to ensure that customers who rely on 3G networks for mobile internet access are not affected. VMO2 said its 4G network already covers 99% of the UK population, and its 5G services will cover half of the population by the end of this year.

But to access these more advanced networks, customers need end devices that support the technology. VMO2 said that once the 3G shutdown is completed, the vast majority of customers will not lose network connectivity, and the company has promised to provide support to customers who may be affected. The operator emphasized that it would contact users in advance to let them know about the change and promised to work with consumer groups and charities to help manage the network transition.

In the meantime, voice calls and text messages will continue to operate on the 2G network until the 2G network is also shut down. However, the shutdown of 2G networks may be more challenging due to IoT connectivity and voice roaming issues and is expected to occur in 2033.