A 17-year-old boy said he had no choice but to "jump in" when he saw a mother and her child struggling in the River Barrow in Co Carlow.
Miley Doran said he jumped into the water after the mother’s attempts to rescue her daughter were unsuccessful.
Stacey Foley and her 13-year-old daughter Sophie Foley-Smith were on a family outing when Sophie was dragged by a current into the river.
Speaking on RTÉ's News at One, Miley said: "It was a warm day, and I was swimming as usual. I glanced over to the right, and I saw the child slip in. Her mother jumped in after her. There was another child who was screaming, 'Help! My mother is drowning'.
"So, when I ran over to see what was happening basically the woman was screaming in fear of her life.
"I had no choice but to jump in and pull the two of them out. I managed to get her out safely and soundly.
"When I saw them drowning, I had to do the right thing."