"It was much harder than I think any of us thought," said 61-year-old Colleen Shields. "It took a toll."
The swimmers arrived on shore in Whitby, Ont., to a celebration of friends and family. The gruelling swim spanning five days, four nights included two-metre-high waves, icy water and a thunderstorm that forced the team to temporarily seek shelter.
Originally the team planned to swim from Kingston to Burlington, but the end came sooner than expected due to safety concerns including falling water temperatures. They completed 242 kilometres of the planned 305-kilometre route.
"We're all really tired but we're all really happy that we accomplished what we did do," Shields said, adding that she's a "little disappointed" to end the route early. "You can't win against Mother Nature."
On Friday, the youngest member of the team, Mona Sharari, 18, had to leave the relay to be treated for exhaustion and dehydration. But she returned on Saturday to make the final one-kilometre push with her teammates.
"We had a full-team finish," Shields said.
If the team had finished the entire route, it would have been the first time in history a relay team swam the length of Lake Ontario.
All of the women on the team — who are aged 18 to 61 — are accomplished long-distance solo swimmers.
Sharari swam the English Channel last year. Shields and her teammates Nicole Mallette, 48, Samantha Whiteside, 23, and Rebekah Boscariol, 18, have all completed the solo swim across Lake Ontario, a 52-kilometre stretch from Niagara-on-the-Lake to Toronto.
The crossing was first completed by a 16-year-old Marilyn Bell in 1954 and includes an overnight solo swim through cold and often rough waters.
Since Bell's swim, the crossing has been done 56 more times — mainly by female swimmers.
The team are still hoping to raise $300,000 for Plan International's 'Because I am a girl' campaign, which promotes rights and opportunities for girls in Canada and abroad.
Mallette estimated they had reached $18,000 by Saturday.
She said given the intensity of the swim, the teammates agreed they wouldn't try to do it again.
"Physically and mentally for the first two days we just got hit big time," she said, adding the experience was an achievement for "five incredible women" and an unforgettable feat.
"Every obstacle Lake Ontario could throw at you was thrown at us in the last five days," she said.
—Written by Clare Clancy from Toronto