South Australia has thrown its borders open to all states and territories for the first time in months, with thousands of travellers expected to arrive in the days and weeks ahead.

From Tuesday, people from Victoria, NSW and the ACT are allowed to enter SA along with those from Western Australia, Queensland, Tasmania and the Northern Territory, although some restrictions and requirements will remain in place.

Everyone must be double vaccinated and use a online border entry process known as EntryCheck SA, which assesses an individual’s vaccination status, departure location and COVID-19 risk.

Based on the information provided, travellers may also be prompted to use a new HealthCheck SA app, which will help them monitor daily symptoms and guide them through any testing and quarantine requirements.

Unvaccinated travellers will be required to seek a special exemption and applications will be assessed on a case-by-case basis.

By Monday, more than 25,000 people had applied to come to SA, with most of the earlier arrivals expected to be returning residents or people reuniting with family and friends.

Tourists are more likely to travel to SA over the Christmas-New Year holiday period.

Premier Steven Marshall said the state’s border restrictions were in place for good reason, but it is time to allow people to be reunited with loved ones and for others to pursue business and travel opportunities.

“There will be some pretty happy faces down at the airport and at our borders as people start to come back into South Australia,” he said.

“They’ve got to be fully vaccinated but we certainly will be welcoming them with open arms.”

The relaxation on border rules comes despite SA still being short of its original target of having 80 per cent of those aged 16 and over double dosed.

As of Monday, federal government figures put the vaccination rate at 77.4 per cent.

Some local virus measures also remain, including a requirement to wear masks in venues such as shopping centres and on public transport.

SA had no new virus cases on Monday and has two active infections, both in people who acquired the disease overseas.

-AAP