Conducive weather in the morning helped Country Fire Service (CFS) crews around the Kyeema area to build containment lines around the fire, according to The Advertiser.
About 100 firefighters are still in the area, reported ABC.
The fire has burnt more than 90 hectares since breaking out on Tuesday.
CFS incident controller Scott Turner said conditions were quite favourable for firefighters today.
“Early this afternoon CFS has declared the Kyeema fire contained,” he said.
“We’ve managed to secure 100 per cent of the fire reach, although there will be smoke from the fire ground and potentially there will be some burning material inside the fire for the next three to four days.
“The threat has dramatically reduced although the community has to be vigilant and the CFS will keep volunteers there for a couple of days monitoring activity for the community’s safety.”
He said Wednesday was a particularly difficult day for the volunteers on the fire ground.
“Firefighters worked in very hot and very windy circumstances — they couldn’t see more than 30-40 metres on the fire ground so it was an enormous effort by our volunteers in very trying conditions,” he said.
Mr. Turner said anyone doing burn-off work on their properties needed to ensure they kept appropriate firefighting equipment close at hand.
“People also need to monitor the areas they’re working on for a number of days afterwards,” he said.
The Education Department said catastrophic fire danger ratings led it to close some state schools and preschools in bushfire-prone areas of the Riverland, Mid-North, Flinders and North-West Pastoral regions on Thursday.
The Environment Department said some national parks and reserves were closed on eastern Eyre Peninsula, in the far north, the Mid-North, Flinders Ranges, Riverland and Murraylands.
SA Power Networks urged people to keep their mobile phones charged and battery-powered radios on hand in case of power outages.
The CFS has declared total fire bans for Friday in the Northwest Pastoral and Northeast Pastoral — both have a danger rating of severe.