Melbourne marathon swimmer Chloe McCardel has overcome jellyfish stings, exhaustion and hypothermia to complete a remarkable 128-kilometre swim across the Bahamas.

The 29-year-old has secured her place in the world record books, completing the longest open-water solo, continuous unassisted marathon swim ever.

She suffered several setbacks during the gruelling challenge, including multiple jellyfish stings just 13 hours into the open-water swim, which started at the southern tip of the island of Eleuthera.

Chloe, who has previously set records for swimming 60 laps across Bondi Beach and completing two non-stop double crossings of the English Channel, admitted the record swim, which took months of planning and research, was a very tall order.

Above: Chloe McCardel completes record-breaking ocean swim.