A Calgary mother is being called a hero after she was the only person to swim out and rescue a Montreal couple from drowning in Mexico.

Tamara Loiselle was taking an early-morning walk on a beach in Cancun in late December, when she noticed a couple struggling a few hundred feet out in the water.

Security guards at a nearby condo grabbed a rope and life preserver but only Loiselle was willing to dive into the water to save the two.

"Those people were probably going to drown if I didn't go in," she told CTV Calgary. "So they grabbed the rope and put it around my waist, and they gave me a life preserver and I went into the water."

The 42-year-old single mother of two relied on her strong swimming skills to battle the huge waves as she swam out to the couple.

Loiselle said she decided to become a triathlete after she nearly drowned six years ago. At the time, she had fallen off a boat and had struggled to get back on board. She said the accident made her determined to get stronger.

"It was from that incident that I resolved I was never going to be that weak and out of shape again," she said.

As for the Montreal couple, they wish to remain anonymous but say they are eternally grateful for Loiselle's bravery.

The man told CTV Calgary that she undoubtedly saved their lives.

"She's a true hero. Nobody on that beach – the dozen men that were there – nobody was willing to jump in," he said. "I told her that words cannot describe my gratitude. There's nothing I can say or do to reflect the extent of what she's given us."

After thanking her on the beach, the couple reached out to Loiselle on Facebook and even wrote her a letter of gratitude. Loiselle said the woman told her that before she was rescued, she thought she was going to die.

“She thought she was dying and I was her angel, so it was really heartfelt,” Loiselle said, adding that she plans to reunite with the couple in the future.

Meanwhile, Loiselle's two children are beaming with pride at how their mother stepped up to help others.

When asked how he felt about his mother, Loiselle's son Sasha simply said he was "really happy."

With a report from CTV Calgary's Shaun Frenette