Connor Telford, 17, visited Penllergare Valley Woods on Monday while on holiday in nearby Mumbles, Wales for a week with his girlfriend.
While in the park, he noticed a dog was struggling to stay above water after chasing some ducks into a pond.
Acting quickly, Connor kicked off his trainers and ran into the water to save the seven-year-old Shih-Tzu, called Charlie, from drowning.
Onwer Jane Warner, from Glais, unable to do anything to save her dog due to a disability, watched the whole rescue unfold in front of her.
"This young Scottish lad is my hero,” she said.
The story has since made headlines across the UK and the pair have spoken about the dramatic rescue together on BBC Wales.
Speaking about the moment Charlie entered the water, Jane said: "It was only the second time I’d taken Charlie to Penllergare Valley Woods, and the first time around he’d shown no interest in the ducks whatsoever.
“But on this occasion, he jumped in the lake to paddle after them, but I knew he had no chance of catching any – those birds were giving him the proper runaround.”
It was at that point Jane, 50, a former accounts manager, noticed Charlie was tangled up in the reeds and couldn’t stay above water.
“I’m disabled, so there was no way I could’ve swum out to get him,” she said.
"Which just left me standing there helpless on the bank thinking, ‘What the hell do I do now’?”
“But before I knew what was going on Connor had dived in.
“By which time there was no sign of Charlie at all – he’d gone completely under.
“Had he not got right to him he’d have died.
“And the poor lad himself was also quite shaken up afterwards. I think it had been a tougher swim than he’d expected and I’m really grateful to him for risking his own safety the way he did.”
Too shaken up by Charlie’s accident, Jane forgot to take down Connor’s details, but soon found him after launching a search for him on social media shortly after the rescue.