"They saved her life; there is no doubt about it," Tony Kramers said yesterday.
"She would have drowned as there is no way she would have had enough energy to swim the 20m back to shore."
The 54-year-old has now been moved to a Dunedin Hospital ward after spending most of the week in intensive care recovering from her ordeal.
On Tuesday, shortly after 9pm, the woman was driving towards her Portobello home when she failed to take a corner in wet conditions at Raynbird Bay.
"She can't remember going off the road, but she remembers being stuck in the car as the doors wouldn't open and it started to fill up with water," Mr Kramers said.
She took several deep breaths of air from the roof cavity of the car before it "went chock-a-full of water and she popped up ... and that is all she remembers".
Mr Kramers said two people in a passing car, who spotted the lights of the semi submerged car as it floated towards the channel, plunged into the cold water.
The pair - a research doctor and theatre nurse - swam 20m to save his mother, who bobbed up and down several times.
"She would never have made it back to shore if those guys hadn't saved her ... she had a lot of water in her stomach; 90% of her lungs were full of water.
"She just about drowned and was very, very lucky," he said.
"The pair were heroic to strip down to their undies and paddle out in the freezing cold to save someone they didn't know."
Near the shore, the trio were assisted by other passers-by. The woman was taken to Dunedin Hospital in a deteriorating state.
The pair left the accident scene shortly afterwards.
Later, one of the men visited the woman in hospital. Her family would like the men recognised for their bravery, Mr Kramers said.
Senior Constable Lox Kellas, of Portobello, said police were yet to locate the men but praised their actions.
"It was a fairly courageous effort."
