It was a dramatic rescue near Keswick on Friday, where York Regional Police pulled four men to safety after they broke through the thin ice of Lake Simcoe.
A fifth man was able to make it back to the shore on his own.
Investigators told 680News, the men were ice-surfing, using kites, when they fell through the ice off the shore near Ravenshoe Rd. at around 5 p.m.
They were in the water for about 30 minutes before they were rescued. All were conscious at the time.
None of the men, ranging in age from 30 to 67-years-old, were wearing life jackets.
Three of the men were taken to Southlake Regional Health Centre in Newmarket, while a fourth was taken by air ambulance to St. Michael's Hospital in Toronto. All were suffering from hypothermia. One of the men remains in critical condition.