The young pair bravely sprang into action, using their extensive surf lifesaving education to save the life of a teenager who had become caught in a rip outside patrol hours at Corrimal on Saturday.

Clare, 13, had taken younger brother Daniel, 12, out for a lesson on their race boards following twilight nippers when the drama unfolded.

About an hour into their session, they noticed three men frantically waving and pointing to the waves from the shore.

The two saw a surfer trying desperately to keep 13-year-old Eben Bajgar afloat on his sinking board about 250m away.

Without hesitation the St George siblings paddled to the mystery boarder and struggling teen, Daniel reaching the scene first after Clare fell momentarily from her board.

But the inexperienced Daniel could not pull Eben to safety on the tricky race board and instead Clare, the 2010 Illawarra Branch Junior Surf Life Saver of the Year, came to the rescue.

"I knew what I had to do," she said. "It was a bit scary but I think I was more scared for what could happen to Eben."

Using strength beyond her size, Clare kept a cool head and managed to drag a panicked Eben onto the board, and with the help of her brother, ferried him to shore on a wave.

He was reunited with terrified father Peter Bajgar who had unsuccessfully tried to save his son before help arrived.

Mr Bajgar said he was in awe of the bravery and skill of the young rescuers.

Eben was treated by ambulance officers at the scene and given the all-clear to go home.

Yesterday the Wollongong High School student was coming to terms with his experience and said it hadn't put him off going to the beach forever, although he would do things differently next time.

"I think we'll be going back again soon, I like going to the beach," he said.

"It has taught me to stay between the flags and not to swim at a beach that isn't patrolled."

Eben thanked the duo for their bravery.