The woman was fully vaccinated with Pfizer.
Covid-19 has jumped the border from Victoria to South Australia with a new case announced in Adelaide on Saturday.
The state’s Deputy chief health officer Emily Kirkpatrick said a woman in her thirties who recently returned from Victoria had tested positive to the coronavirus.
She arrived in South Australia on Friday evening by plane with an exemption to return home from the Covid-plagued eastern state.
Her Jetstar flight, JQ778 from Melbourne, is now an exposure site, as is the ground floor female bathroom at Adelaide Airport near the baggage carousel between 5.55pm and 6.15pm.