The state topped CommSec's April State of the States report, which gauges the economic momentum of each region, after also ranking first in January.
CommSec chief economist Craig James said South Australia was doing well but there were signs its economy was losing momentum and it was possible another front-runner, Western Australia, could catch it.
"Western Australia has the necessary momentum to pass South Australia to attain top spot in coming quarters," he said.
States are assessed across various indicators such as retail spending and new home building starts to see how they are doing compared to "normal", or the decade average.
WA topped the charts for population growth - that is, how quickly it is growing compared to 10-year trends - although most states and territories have had fast-expanding populations since borders reopened after the COVID-19 pandemic.
WA was also strongest on business investment, while the ACT led on retail spending.
Mr James said state and territory economies were generally faring well despite clear challenges.
"Overall, economies have slowed in response to higher interest rates, but have generally remained resilient, underpinned by firm population growth and low unemployment," he said.
HOW THE STATES FARED
1st: South Australia
2nd: Western Australia
3rd: Victoria
4th: Tasmania, Queensland, NSW and the ACT
8th: Northern Territory
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