A 13-year-old boy saved his mother and two younger siblings on Friday evening, swimming four hours in fading light and rough conditions, after they were swept out to sea in South West Western Australia.

The family were holidaying in Quindalup, 250km south of Perth, when strong winds pushed their inflatable paddleboards and kayak offshore from Geographe Bay.

The boy attempted to kayak back to shore to get help, but the vessel took on water, forcing him to swim 4km back to shore, where he successfully raised the alarm.

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Western Australia police received a report that a family had been swept out to sea at 6pm on Friday and a multi-agency search and rescue operation was mobilised – including WA water police, local marine rescue volunteers and Western Australia’s rescue helicopter.

The woman, 47, a boy, 12, and a girl, 8, were located by the rescue helicopter at 8:30pm, clinging to a paddleboard.

A volunteer marine rescue vessel was directed to their location and all three were successfully rescued.

Naturaliste Volunteer Marine Rescue’s commander, Paul Bresland, said the family was located about 14km offshore and had been treading water in rough seas for hours before they were found, the ABC reported.

Bresland said the 13-year-old gave a detailed description of the colour of the kayaks and paddleboards – invaluable to search efforts.

He also revealed the 13-year-old swam for two hours with his lifejacket on, before taking it off, swimming another two hours without it.

The family were assessed by St John WA paramedics before being conveyed to Busselton health campus for medical assessment.

A spokesperson for St John WA said it was a “remarkable rescue” and that he “praises the teenage boy for his brave actions”.

South West police inspector James Bradley thanked those involved in the successful rescue mission and said it was a reminder that ocean conditions can rapidly change.

“Thankfully, all three people were wearing lifejackets, which contributed to their survival,” he said.

“The actions of the 13-year-old boy cannot be praised highly enough, his determination and courage ultimately saved the lives of his mother and siblings.”