The 10-foot (3-meter) adult female was one of 194 whales and seven bottlenose dolphins that became stranded Sunday evening on Naracoopa Beach on Tasmania state's King Island.
Up to 150 volunteers helped wildlife experts to refloat 53 surviving whales and five dolphins on Monday. But wild seas whipped by strong winds prevented a second rescue attempt of the lone stranded female until Wednesday, when it was slung between two jet skis and towed out to sea, Tasmania's Parks and Wildlife Service manager Chris Arthur said.
"The whale was seen to swim toward a group of whales in the area, several of which had been tagged by rescuers two days earlier," Arthur said in a statement.
He described the three-day operation as one of the largest successful whale rescues in the island state's history.
But a total of 140 whales and two dolphins died on the beach overnight Sunday, despite the frantic rescue efforts to keep them moist and upright.
It was not clear why the animals had beached on the island, halfway between Tasmania and mainland Australia.
Strandings happen periodically in Tasmania as whales go by during their migration to and from Antarctic waters, but scientists do not know why it happens.
Most of Australia's whale strandings occur around Tasmania.
In January, 45 sperm whales died after becoming stranded on a remote Tasmanian sandbar, even though rescuers worked for days to keep them cool and wet as they tried to move them back to the open water.
Last November, 150 long-finned pilot whales died after beaching on a rocky coastline in Tasmania. A week earlier, rescuers saved 11 pilot whales among a pod of 60 that had beached on the island state.
CLICK HERE to follow Action News on Twitter
CLICK HERE to get Action News on your website
CLICK HERE to find Action News on Facebook