From of 12:01 am, Monday 12 April 2021

Travellers may enter South Australia from the whole of Queensland without restrictions (previously, those from City of Brisbane, Logan City, City of Ipswich, Moreton Bay Region and Redland City had been subject to Level 3 restrictions).

Note: All travellers must complete the Cross Border Travel Registration prior to their travel to South Australia. Travellers must complete a separate Cross Border Travel Registration for each person in the travelling party including all children. People will experience delays on arrival if they have not completed an application for each person.

https://www.covid-19.sa.gov.au/restrictions-and-responsibilities/travel-restrictions