The King's High School pupil was admitted to the Dunedin Hospital intensive care unit after being swept off rocks at Cape Saunders on Sunday afternoon while fishing. He was discharged from the children's unit on Wednesday night.
He was battered and bruised after spending more than an hour in the freezing water, without a wetsuit or life jacket.
Kane, a year 10 pupil, said he thought he would die.
"I just remember swimming upwards and it was all blue. It took ages to reach the top. I thought I was going to die and it would be short and sweet.
"They say drowning is peaceful but it's not - it's really panicky."
Kane tried to kick off the skinny jeans he was wearing, but they caught around his ankles and made it hard for him to float.
After five minutes in the water he was exhausted, and was soon cold and had a throbbing pain in his head.
"I was freaking out," he said.
The teenager slipped in and out of consciousness and did not remember being rescued, just waking up in the intensive care unit about midnight.
His body temperature had dropped from 36degC to 27degC.
Yesterday, he was just happy to be alive and to be at home to celebrate his birthday with friends and family.
Both his arms are in plaster and it will be at least 10 weeks before the cast is removed from his left arm.
"I snapped the wrist of my left arm and my right arm is fractured," he said.
While in hospital Kane was visited by three Highlanders and he received a birthday card from the local marine search and rescue team.
His family wanted to thank all who helped rescue him, including the Otago Regional Rescue Helicopter crew, as well as the nurses and doctors who cared for him.
Kane said his best friend, Micah Wharerimu (14), who raised the alarm on Sunday, deserved a special thank you.
Asked if he would do the same to save Micah, Kane said he would be "a bit faster".
Micah, a fellow King's High School pupil, said he had since reached hero status among classmates.
The pair planned to continue fishing, just not at Cape Saunders.
