Swimming and learning to swim is such an important part of Australian life and culture than many traditional Muslim women are taking part by wearing a "burquini" - designed by an Australian, Ahead Zanetti. You can see a woman in this photo wearing one. They have been adopted by the Surf Life Saving Association for Muslim women members - see article here
Here's an article about Mecca Laa Laa on patrol at North Cronulla beach. (My sister taught Mecca).
Personally, I love to feel the water on my skin and would feel too restricted, but, hey, if it helps some young women learn to swim, interact with their children in the water, and feel comfortable and culturally included, more power to them.
There's lots more pictures of Shelly beach, here on my "Swimming" blog.