Sophie Tucker, apparently named after a late US entertainer, fell overboard as Jan Griffith and her family sailed through choppy waters off the northeast Queensland coast in November.
The dog was believed to have drowned and Griffith said the family was devastated.
But out of sight of the family, Sophie Tucker was swimming doggedly and finally made it to St Bees Island, five nautical miles away, and began the sort of life popularised by the TV reality show "Survivor."
She was returned to her family last week when Griffith contacted rangers who had captured a dog that had been living off feral goats on the largely uninhabited island, in the faint hope it might be their long-lost pet.
When the Griffiths met the rangers' boat bringing the dog to the mainland they found that it was indeed Sophie Tucker on board.
"We called the dog and she started whimpering and banging the cage and they let her out and she just about flattened us," Griffith told the national AAP news agency.
"She wriggled around like a mad thing."
Griffith said that when the dog was first spotted on the island she had been in poor condition.
"And then all of a sudden she started to look good and it was when the rangers had found baby goat carcasses so she'd started eating baby goats," she said.
Sophie Tucker, a member of the Australian cattle dog breed, had been quick to readjust to the comforts of home, complete with airconditioning, Griffiths said.
"She surprised us all. She was a house dog and look what she's done, she's swum over five nautical miles, she's managed to live off the land all on her own," Griffiths said.
"We wish she could talk, we truly do."