A 13-year-old boy in Western Australia swam about 4km through rough waters to save his mother and two siblings after they were swept out to sea while paddleboarding and kayaking.

Strong winds pushed the family offshore at Geographe Bay, and the boy swam back to shore after his kayak took on water to raise the alarm.

Rescue services launched a search, and a helicopter later found the boy’s mother and two younger siblings clinging to a paddleboard about 14km offshore.

All three were safely rescued and returned to shore, the BBC has reported.

Authorities praised the boy’s extraordinary bravery and said the incident highlights how quickly ocean conditions can change.