Nine-year-old Molly Wildsoet was playing in hip-height water between the flags on Woonona Beach when she ducked under a set of waves, only to resurface out to sea.

"The water had been calm, and with only small waves, it looked ideal," said Molly's mum, Kyla Wildsoet yesterday.

"A rip was moving up the beach so quickly, even the lifeguards couldn't move the flags fast enough, so they chose to concentrate on closely watching the swimmers instead,"she said.

While the ordeal was frightening, Molly said she was glad her swimming skills kicked in and kept her positive and afloat.

"I first thought, 'I'll be OK, I can swim'. But as I kept swimming, I realised the rip was too strong and I couldn't get out of it," she said.

"I was between the flags, so I knew someone would come and help me.

"So I just tried to keep calm.

"The lifesavers did come," Molly said.

Mrs Wildsoet said she was amazed by her daughter's maturity in such a stressful situation.

"Many children would have panicked at that point, but Molly had been doing swimming lessons at Northern Stars Swim School for some time, so it was great to see how those skills kicked in," Mrs Wildsoet said.

"She was able to help save her own life."

Lifeguards rescued Molly and brought her back to shore.

She wasn't put off by her ordeal, however, and dived back in the surf with her friends.

Molly's swim teacher, Raelene Jones, said Swim Australia swim schools, which include Northern Stars, teach children and adults the life skills they need to keep them safer in and around water.

"Because the majority of children who attend our swim school live near the coast, we include education on beach safety in our program," Mrs Jones said.

She said it is imperative every child and adult know how to swim and to identify hazards in water.