Nova Scotia RCMP say the woman was alone in the dinghy near Marshville, Pictou County, when the tide changed and she was taken some distance from the shore.
The Canadian Coast Guard and firefighters from the River John Volunteer Fire Department went to search for the woman around 8 p.m.
The woman was found a short time later but she was not responsive. She was taken to hospital where she was pronounced dead.
RCMP Sgt. Al Leblanc says the woman did not have a paddle and it does not appear she fell in the water.
The cause of the woman’s death has not been released and the medical examiner is helping with the investigation. Police say they do not suspect foul play.
The woman was visiting family in the area.