Frontline health workers at the Murray Bridge Hospital, east of Adelaide, will be the first to get the AstraZeneca coronavirus vaccine.
Prime Minister Scott Morrison has confirmed the batches that arrived from overseas recently have been tested and given the tick of approval.
They are being distributed to the states for release, with SA to be the first on Friday.
SA Health Minister Stephen Wade said early access to the second vaccine option would give the state the opportunity to reach further into regional areas.
He said the Murray Bridge Hospital would act as the base initially distributing about 1000 doses across the southern Riverland region.
"There will be a focus on frontline health workers but also in that region, there are a large number of residential aged care facilities," he said.
"Both the residents and staff at those state-run facilities will be part of this vaccination push.
"Police in the region will also get their AstraZeneca vaccine.
The rollout will start slowly with about 40 jabs expected to be delivered on Friday, increasing to about 90 doses each day.
Next week SA will also open two new hubs to distribute the Pfizer vaccine, at the Lyell McEwin Hospital in Adelaide's north and at Mt Gambier in the state's southeast.
While Mr Morrison said the next significant phase in the vaccination program would involve approval of the manufacturing process in Australia for the AstraZeneca vaccine.
Pharmaceutical giant CSL will manufacture 50 million doses of the variant, which most Australians will receive.
SA reported no new coronavirus cases on Thursday with only four active infections remaining in hotel quarantine.
It said 2683 Pfizer vaccinations had been delivered so far.
Australian Associated Press