It's been a feature of phone coverage for decades, but within a year all of Australia's 3G networks will have been switched off.
The shutdown will begin in December of this year, and is expected to impact millions of devices across the nation.
This is what you need to know about it.
When is the 3G network shutting down?
Australia's 3G networks will shut down in stages, beginning in December.
Vodafone will be the first company to switch off its network on December 15. Telstra will follow, with all its 3G services ending on June 30, 2024, while Optus will be the last to shut its 3G doors in September 2024.
How many people will the shutdown affect?
While we don't know exactly how many people the shutdown will impact, an estimate earlier this year put the number of 3G-reliant devices in Australia at about 3 million – most of which are older ones that have been around for at least five or six years.
All of them will stop working after the shutdown.
These include phones, eftpos machines, cars, tablets and security cameras.
Concerningly, it's estimated that 200,000 of those devices are medical alarms.
"An elder or someone else with a vulnerability who is relying on that alarm for an emergency response simply won't get one," David Waldie from medical alarm company Eevi said.
There are some concerns that switching off the 3G network will reduce mobile coverage in regional areas that don't yet have access to 4G or 5G.
Telstra said it is committed to providing 4G coverage in all 3G areas before the shutdown. Optus has made no such commitment on its website, while Vodafone said its 4G coverage is "similar in size" to its 3G offering.
How do I find out if my device is affected?
The easiest way to find out whether a device you have is going to be affected by the shutdown is to contact the manufacturer.
"Don't put off checking that device, make sure you get to that as soon as possible to make sure you're not caught out," Stephen Fenech from Tech Guide said.
You can also get in touch with your phone provider – Optus has even put out a list of its 20 most-used devices that will be impacted, which includes the iPhone 5, 5C and 5S, Google Pixel 2 XL, and Samsung Galaxy S5.
Some companies, like Eevi, are reaching out to customers to make sure they stay connected.
What can I do if my device will be impacted?
In short, you'll need to purchase a replacement that is compatible with the 4G or 5G networks if you want to keep accessing phone and internet services.
In some cases, this might be as simple a task as changing your SIM card from a mini or micro SIM to a nano one, while in other cases you may need to buy a whole new phone or other device.
Why is the 3G network shutting down?
While 3G used to be the main pillar of mobile coverage around Australia, it's now used far less frequently, as modern devices instead rely more on the faster 4G and 5G networks.
That means phone providers have a huge amount of their network dedicated to a service that isn't used – and is only going to become less and less relevant in the future.
By shutting down 3G coverage, a provider like Telstra or Optus can take the radio frequency bands it used for that network and repurpose to improve and expand 4G or 5G coverage – a process known as "re-farming".
"The demand and the consumption of data has been increasing exponentially," Chris Taylor from Telstra said.
"That's why we need to move our customers onto the 4G and 5G networks."
The process isn't unique to Australia – similar 3G shutdowns have happened or been announced in the UK, USA and New Zealand.
