Telstra is counting down the hours until the final shutdown of mobile services on the 3GIS network begins.
The carrier will axe services on the Hutchison-operated network on Friday August 31, capping several years of planning efforts.
The 3GIS network was launched in 2004 in mainly metropolitan areas of Australia under a network sharing arrangement between Telstra and Hutchison 3G Australia.
For Telstra, 3GIS was superseded by the faster Next G network that launched in October 2006.
"[On Friday] at 10am Telstra will commence the carefully planned closure of services on our earlier 3G network operating on the 2100MHz band," Telstra Networks executive director Mike Wright said.
"Our team has been preparing for this change for two years and nothing has been left to chance.
"Customers have been individually contacted to remind them of the network changes."
3GIS was Australia's first 3G network. Its wind-down has been ongoing, particularly over the past several months.