Three abandoned cottages were destroyed along Lake Simcoe in Innisfil early Friday morning.
Fire crews were alerted to the fire on Leonard Street just after 6:00 a.m.
The fire was put out within an hour and nobody was injured.
Fire officials tell CTV News that there was no power being supplied to the cottages but they are not treating the fire as suspicious.
Neighbours also tell CTV News that the location was a popular hangout out for teenagers.
Investigators remained on the scene on Friday trying to determine the cause and the damage amount. It is not known if the Ontario Fire Marshall will be called in.