Tamara Loiselle, a Calgary triathlon competitor, is being credited with saving the lives of a Montreal couple she spotted in distress in the waters off Cancun, Mexico.

Loiselle and a friend first heard cries for help around 7:30 a.m. CT on Dec. 29.

“We all ran out to the beach because we could hear a man screaming for help,” she said.

Loiselle said one of the security guards brought a life-preserver, then another two guards rolled out rope from a big reel.

"We were kind of all just standing there kind of looking to see who’s going out, how is this unfolding," she said. "There was no lifeguard. It seemed apparent that none of the security guards would be able to swim out."

Loiselle, who competes in triathlons and worked as a lifeguard as a teenager, volunteered to attempt to rescue the struggling swimmers.

Swimming out with the rope around her waist, clutching the life-preserver, Loiselle quickly realized how big a challenge she was facing.

“The waves were quite large,” said Loiselle, who estimated the couple had drifted as much as 60 metres away from shore.

'What did I get myself into?'

Loiselle said she struggled to swim underneath the fast-breaking waves.

“I got knocked around a little bit, at one time I got … the wind knocked right out of myself,” she said.

“I did have the thought about, 'Oh my God, what did I get myself into?' and 'I hope this works out well, because I have two small children at home.'"

Loiselle said that as she got closer it was clear the couple were in serious trouble.

“Once he could see me, you could tell he was very relieved, and then he pointed out a little farther and he said, ‘Go to her first,’” she said.

“And then when I looked out farther I could see a woman that was completely exhausted. Just her face was sticking out of the water, gasping for air.”

Loiselle used the rope and life-preserver to help bring the couple to shore.

“As soon as I felt the rope starting to tow us in I was like, 'Oh thank God … everybody's going to be OK,'” she said.

Loiselle said she is still in contact with the couple.

"The woman called me on the phone today," she said Monday. "She said that she 'had given up, thought she was dying and was looking at the sky' then 'saw your face and thought you were an angel.'"