A fire ripped through a houseboat moored near the boat ramp at the corner of Bertram Street and Nairn Road in Coodanup on Friday afternoon.
Fire crews from both the Mandurah and Falcon brigades were called to the scene after the initial report came through at about 11.30am, with the Department of Fire and Emergency Services describing the boat as "fully alight."
The blaze gutted one end of the boat with significant damage noticeable, before it was eventually extinguished by firefighters at about 12pm.
No people were on board the boat at the time of the fire.
WA Police and the Department of Marine Safety also attended the incident.