Five women hoping to complete a gruelling non-stop relay swim across the length of Lake Ontario in five days are pushing on, despite falling behind schedule.

The women -- ranging in age from 18 to 61 -- have been battling 1.5-metre waves since they began their 305-kilometre journey on Tuesday.

By Thursday evening, they were approximately eight hours behind schedule.

They plan to arrive in Burlington on Saturday.

"We really prayed and hoped that the waves would come down eventually," Rebekah Boscariol, one of the five women on the "Because Girls Can" team told CTV Toronto Thursday, around 13 km from shore just west of Presqu’ile.

Swimming with Boscariol, 18, are Colleen Shields, 61, Samantha Whiteside, 23 and Nicole Mallette, 48, all of whom have previously completed 52-km solo swims across Lake Ontario from Niagara-on-the-Lake to Toronto. Mona Shariri, 18, the fifth member of the team, successfully crossed the English Channel last year.

In addition to the inclement weather, the women have also been battling fatigue, sea sickness and boredom. "You just daydream (to) keep yourself busy,” Whiteside said.

Despite the hurdles the women have been facing, Mallette said giving up is not an option.

"We’ve got a long way to go still but knowing that we're coming home is much better," she said.

A relay swim across the length of Lake Ontario has never been accomplished before. The “traditional” solo swim across Lake Ontario was first successfully completed by 16-year-old Marilyn Bell in 1954.

Since Bell's swim, the gruelling crossing – which involves an overnight swim through cold and often rough waters – has been completed 56 more times.

The women's progress is being tracked by four sailboats and three zodiacs. The boats also provide a place to rest and eat when the women are not swimming.

In addition to being the first team to complete a relay swim across Lake Ontario, the women are also attempting to raise $300,000 for Because I Am A Girl, a charity that promotes opportunities for girls in Canada and abroad.

With a report from CTV Toronto's Zuraidah Alman