A brave 13-year-old boy has spoken of his exhaustive efforts to alert authorities when his family was swept out to sea on WA’s south-west coast.

Austin Appelbee and his family were paddleboarding and kayaking at Geographe Bay, near Quindalup, on Friday when rough conditions pushed them out to sea about 6pm AWST.

The teen began to head to shore to raise the alarm after his mum and two younger siblings became stranded.

The family came into trouble while kayaking and paddleboarding at Geographe Bay on Friday. (Nine)
Austin Appelbee said he was thinking of his family to get him through. (Nine)

But he was forced to abandon his kayak when it began to take on water and instead swam more than four kilometres to shore.

“Two hours without a life jacket on and yeah, he made it. Superhuman effort,” Marine Rescue commander Paul Bresland said.

Austin said he was thinking of his family to push him through the swim.

“I just said ‘alright. Not today, not today, not today’,” Austin said.

Austin’s mum Joanne was rescued from the water after her son raised the alarm. (Nine)

“I did breaststroke, I did freestyle, I did survival backstroke.

“I hit the bottom of the beach and I just collapsed and then after that I had to sprint two kilometres to go get to the phone.”

Austin’s mum Joanne Appelbee and siblings, aged 12 and eight, were found by emergency services clinging to a paddleboard after spending nearly 10 hours in the water.

The trio were taken to Busselton Health Campus and have since recovered.

Joanne said all her children learned to swim at a young age and encouraged other families to do the same.

“There’s no bigger word to describe him other than proud,” she said.

“I’m speechless at his efforts, but at the same time, I knew he could do it. ”