A man in his 30s is in a critical condition after an incident on the banks of the Moore River in Guilderton.
Emergency services fielded reports of a suspected drowning at 10:10am on Tuesday and sent five ambulances to the scene.
Two people were treated at the river, a man in his 40s was taken to Joondalup Health Campus, while the man in his 30s remains on the shore.
A witness who arrived in the small coastal town after the incident told the ABC it appeared a defibrillator had been used near the river mouth.
He said police had cleared the area and were cordoning off the scene.
Guilderton is a holiday town about an hour north of Perth. School holidays began in WA this week.
In 2019, a seven-year-old girl drowned at Moore River while on an outing with her family. Loading Load