Some of the women are concerned about growing Islamaphobia in Australian politics and overseas - but for them, the beach is a break.
The Burkini Babes group has been training for months, getting up early for weekly swims ahead of the south Maroubra competition.
"I don't think I ever had in mind to enter an ocean swim," Yusra Metwally, founder of the group, told SBS.
But after some regions in France banned the burkini last year, and amid a rise in anti-Islamic sentiment across the west, Ms Metwally was prompted to start the group.
"There's a lot going on globally. There's a lot going on politically, and I like to think that when we're in the ocean we get to get away from that," she said.
"We're just a bunch of girls out for a swim; and the more people can see that the more people see diversity on our beaches, diversity in different activities that will hopefully change perceptions that we're just like everyone else."
For the women in the group, the burkini has been liberating - allowing them to reconcile Australian beach culture with Islamic tradition.
"When it first came out it was revolutionary," swimmer Anisa Buckley said.
"It was really amazing, because before then, friends and I would only be able to swim at women-only pool times."
Simon Smith, with the South Maroubra Surf Life Saving Club, said the group's participation was warmly welcomed.
"It's fantastic to have community spirit here, and this is what this swim is all about - increasing that," he told SBS.
Australian designer Aheda Zanetti created the burkini and has sold more than 700,000 across the globe.
"We’re getting enquiries from skin cancer survivors, breast cancer survivors, there are a lot of health issues that have stopped women from having an active lifestyle," she said.
"A lot of them a really excited to have finally found a company to provide a type of swimsuit for them to go back into the water again."
It's a sense of Freedom for Muslim and non-Muslim women alike.
"No one needs to judge us on what faith we are if we choose to be modest while enjoying leisure time like swimming," Ms Zanetti said.