An Oshawa, Ontario teen was saved from drowning in the waters off Shoal Cove beach after a fully-clothed man swam out to her and pulled her away from a strong riptide.

Alexa Lessard, 15, and her younger sister were visiting the beach near St. Lawrence last Wednesday when they were caught in a rip current while playing in the water. Lessard's sister made it back to shore, but Lessard was pulled out to sea.

Brian Murphy battled cold water, high waves and strong currents to help rescue Alexa Lessard. (CBC )

Brian Murphy of Montreal, who was visiting with friends, was getting ready to leave when a couple of girls ran toward him screaming that another girl was drowning.

Murphy said he spotted Lessard about 50 metres away from shore and immediately dived into the water.

Murphy tired by swim

Murphy spent several minutes battling the cold water, high waves and strong current to reach Lessard.

Murphy said by the time he reached Lessard, she had frozen in fear and he was very tired.

"I initially just tried to swim her into shore. I tried to swim with her grabbing onto my shirt, but I couldn't do it at all," recalled Murphy. "I needed her to swim also so I just tried yelling at her, 'You're going to have to swim also.'"

Lessard began to swim on her own and Murphy, concerned about his own safety, let her go, hoping that she would follow him to some nearby rocks.

"I was so tired. I had gassed myself with her trying to swim with her dragging on that I worried myself even about drowning because I was so tired, so I just started swimming and I was just yelling at her that she had to come," he said.

Swam to rocks separately

Lessard and Murphy both managed to reach the rocks separately. Murphy said two of his friends and other onlookers had grabbed a rope and headed to the rocks to get as close to Lessard as possible from the shore.

"They were kind of coaching her on, yelling at her to get in," said Murphy. "And they had thrown the rope out there and they were yelling at her to come in and she made it in, she grabbed hold of the rope and they just pulled her in."

Murphy said after the rescue was over, he was just relieved to know that Lessard was okay.

Lessard and her family didn't want to do an interview about her ordeal, but they did say they would like to see signs posted warning of the dangerous undertow.

St. Lawrence Mayor Wayde Rowsell has said that signage at the beach will be a topic of discussion at the town's next council meeting.