Telstra said this means residents will now be able to enjoy the benefits of 4G, including extra speed and capacity over similar areas that 3G covers.

Telstra's regional general manager for southern NSW, Chris Taylor, said the business announced the closure of the 3G network in 2019.

"Telstra committed to providing equivalent 4G connectivity before we switch off services on June 30, 2024," he said.

"Our recent site upgrades in this area are part of that commitment."

To make the most of 4G speeds, customers with 3G only devices will need to upgrade their device before the June 30 deadline.

"Not all devices are created equal and mobile coverage can be impacted by a number of factors, including the sensitivity of your mobile device," Mr Taylor said.

"Blue tick devices have been thoroughly tested to ensure they're highly-sensitive and able to maximise coverage reach.

"So, for customers who have been using a blue tick device, they'll want to upgrade to a 4G blue tick device to ensure they receive equivalent coverage post-closure (of 3G)."

Leeton shire residents wanting to find out if their devices are 4G capable and suitable for usage after the shutdown can visit https://www.telstra.com.au/support/mobiles-devices/3g-closure.

People can also visit a Telstra store for more information and assistance regarding the shutdown of the 3G network and what to do next.