They will raise funds for the upgrading and expansion of the emergency room at the Red Cross War Memorial Children’s Hospital.
Their goal is to raise R122 million.
Issataya will swim the 8.5km route from Cape Point to False Bay while Abriella will swim the 11.9km route around Robben Island.
The duo will also attempt to break the record for being the youngest people to swim these particular routes and distances.
Although the event only takes place next year, they are hard at work brushing up on their swimming skills.
“On average, I swim about 16km per week. However, the number will increase as we get closer to the event.
“At the moment, I am doing pool training four days per week at Liquid Lines in St Francis Bay. We also do an open water swim on a Friday and Sunday at the canals and the Marina Martinique in Jeffreys Bay respectively.
“This is a good place to train as it has a nice current that is quite realistic,” said Issataya, who believes it is not easy to balance academics and sports.
“When we do get spare time we make the most of it, but academics always takes first preference,” she added.
Abriella said what had prompted them to do the swims was seeing children at a young age fighting life-threatening battles.
“My sister and I want to raise funds for the children and families who are facing challenges every day. We want to fight the battle with them. Seeing children struggle is what motivates us to keep on going. This is not going to be easy but if we put our minds to it, anything is possible,” she said.
Swimming became a big part of the sisters’ lives after they went sailing in the Bahamas a few years ago.
“It became more like a hobby but in 2013, we were introduced to open-water swimming.
“We did not even think of breaking records or raising funds for a worthy cause,” she said.
Last year, Abriella created her own piece of history by becoming the youngest person to swim from Robben Island to Big Bay, raising R158000 for the Red Cross intensive care unit. She swam 7.9km in three hours and eight minutes.
“I felt good about my performance in 2018 and was lucky enough to have the support of so many people. It brought great joy in my heart that I contributed to a worthy course.
“What was special at the cheque handover was the cards I received from the children which I will treasure forever,” she said.
Chief executive of the Children’s Hospital Trust Chantel Cooper said the Bredell sisters were inspiring young women.