Five women will attempt to swim across Lake Ontario lengthwise starting Tuesday morning, in a gruelling 305 kilometre relay they expect will take five straight days of non-stop swimming.

The swim will begin at 10 a.m. in Kingston and is expected to end Friday evening in Burlington.

The women – who range in age from 18 to 61 – will swim in two-hour shifts through the day and night, sleeping and eating on an entourage of sailboats and zodiacs.

All of the women are accomplished long-distance solo swimmers. Colleen Shields, 61, Nicole Mallette, 48, Samantha Whiteside, 23 and Rebekah Boscariol, 18, have successfully completed the Lake Ontario crossing.

Eighteen-year-old Mona Sharari, the youngest member of the group, swam across the English Channel last year.

They’re swimming under the name Because Girls Can and they’re raising money for Because I am a Girl, a charity that works to “end gender inequality, promote girls’ rights and lift millions of girls – and everyone around them – out of poverty.”

The length-wise crossing has never been completed, but the solo crossing from Niagara-on-the-Lake to Toronto has been completed 57 times, the majority of them by women.

The crossing was first completed by Marion Bell in 1954, when she was 16-years-old.