After a month-long investigation, the OPP said Linda O'Leary, 56, has been charged with careless operation of a vessel under the Canada Shipping Act.
Richard Ruh, a 57-year-old NY resident, has also been charged in connection with the crash.
Kevin O'Leary, 65, issued a brief statement after the crash, saying, in part, that he was "a passenger in a boat that was involved in a tragic collision with another watercraft that had no navigation lights on and then fled the scene".
He noted that police have charged the driver of the other boat with operating without a proper light, which may have contributed to the collision.
The two boats collided late at night on August 24 on Lake Joseph in Muskoka, where Mr. Three other people were reportedly injured.
The charges have been laid under the Canada Shipping Act, therefore the Public Prosecution Service of Canada will manage the court processes.
"Because it is before the courts, we're not going to be speaking to any specifics as to how the crash occurred", OPP Staff Sgt. Carolle Dionne told Global News.
He said O'Leary is a "a cautious, and certainly experienced boater" who collided with an "unlit craft on a dark and moonless night on Lake Joseph". According to O'Leary's rep, she passed the test.
In the wake of the tragedy, the 65-year-old was quick out of the dock doing damage control. Ruh purportedly insisted navigation lights were on.
Police later refuted the claim that either boat fled the scene, stating that both groups left to "attend a location" and call 911.
Sources in Muskoka told the Toronto Sun that the OPP has video footage from at least one local cottage in their possession. Suzana Brito, a 48-year-old woman from Uxbridge, Ont., died from her injuries in hospital.