O2 issues important 'switch off' message to UK users - check your phone now

O2 has issued an urgent message to mobile users across the UK as it prepares to shut down its . This move could leave some people without access to or essential services like WhatsApp unless they take immediate action.

The mobile provider is the latest in the UK to join the nationwide phase-out of 3G, following in the footsteps of EE and Vodafone, who have already switched off their legacy networks. Now, O2 is urging its customers to check if their devices are compatible with 4G or 5G, or risk losing connectivity when the changes roll out in 2025.

In an email sent to customers, O2 said: "We recently got in touch to let you know we'll be turning off our 3G services.

"This change has already started, and we'll be continuing the switch off across the country throughout 2025.

"You may currently have a device that's not fully compatible with the UK's 4G or 5G network. After the switch off, you could experience a drop in call quality and be unable to access mobile data, including the internet and messaging apps like WhatsApp."

To help customers prepare, O2 has created an online tool where users can enter their phone's model number and instantly check if it will remain functional after the 3G shutdown.

The network explains that the 3G switch off is part of a broader effort to modernise infrastructure and improve service quality. Since the launch of 4G and 5G, 3G usage has steadily declined, and maintaining it is no longer cost-effective or environmentally efficient.

Redirecting investment to faster, more reliable technologies will allow O2 to expand coverage, deliver better call quality, and offer faster mobile internet speeds across the country.

The full switch-off will begin in April 2025, starting in Durham, and will roll out across the UK over the rest of the year.

O2 customers are strongly advised to check their phones now and upgrade to a compatible device if necessary, to avoid service disruption when the 3G signal goes dark.