From November 23, fully vaccinated people from NSW, Victoria and the ACT will be able to cross into the state.
Fully vaccinated South Australians will also be able to travel interstate without facing two weeks of quarantine on their return.
“We know this is going to be a huge relief for families, for businesses,” Mr Marshall said.
“Those state borders have been extraordinarily punishing.”
Mr Marshall said from the same date, South Australia would be “significantly reducing” testing and isolation requirements.
Fully vaccinated close contacts will be required to quarantine for just seven days, though the infected person will still have to do the full two weeks.
Unvaccinated close contacts will also have to quarantine for two weeks.
All close contacts will still be subjected to three COVID-19 tests.
Casual contacts will have to isolate only until their first negative test result.
Close contacts will be determined by a number of factors, including physical proximity, mask-wearing and vaccination status.
Businesses will also no longer need to close for deep cleaning after exposure.
Mr Marshall also said statewide lockdowns would be a thing of the past.
Chief Public Health Officer Professor Nicola Spurrier said modelling was underway into how any future restrictions would be imposed, and said NSW and Victoria had shown great success in using vaccinations “at the outbreak stage”.
Mr Marshall said all other social and public COVID-19 measures will remain in place until the state hits 90 per cent double vaccination level.
He said the state could expect to pass the 80 per cent mark next week.