Easy way to check if your phone will stop working when 3G network switches off

Telstra said it had seen a significant decline in 3G usage across the national network since it announced the closure of its 3G network almost five years ago.

However, it said approximately 113,000 consumer mobile phones still in use were yet to upgrade ahead of the switch.

"3G accounts for just one per cent of our total network traffic, however we want to make sure everyone is prepared and has an easy way to check the compatibility of their device.

"If the 3G shutdown impacts you, you will likely have already heard from us," Telstra posted on its website.

"But we've also developed an easy to use SMS tool to check if your phone needs an upgrade."

If you're a Telstra customer, or if you have a device that uses Telstra's mobile network, you can find out if your mobile phone is impacted by texting the numeral '3' to the number 3498.

The response will give you the all clear if your phone is already 4G or 5G compatible, but if it's only a 3G phone the text message will offer additional advice on what you will need to do in order to have mobile service after June 30.

Telstra said it was also worth noting some older 4G and 5G phones still use 3G to call Triple Zero.

"When we close 3G, these phones won't be able to call 000 - our SMS checker will advise of this scenario and the need to upgrade your device.

"We are considering all actions to ensure all our customers can call Triple Zero in an emergency after the closure.

"Furthermore, if you or a loved one has a medical alert device, we encourage you to check with the manufacturer that it is 4G VoLTE compatible."

For any questions or to clarify concerns, contact Telstra here.