Naila Yasmin, 43, was found floating face down in the deep end of the unsupervised pool at a Best Western hotel Sunday morning and her 11- and 14-year-old daughters were found floating in the pool's shallow end.
The mother was declared dead at Kingston General Hospital that day, while the 14-year-old died Monday, followed by her 11-year-old sister Tuesday, the Toronto Star reported Wednesday.
Autopsies on the first two victims concluded death by drowning, and an autopsy was scheduled for the youngest child, Ontario Provincial Police said.
The OPP said none of the victims knew how to swim and foul play was not suspected.
The unidentified husband and father was having breakfast with his two sons in the hotel restaurant when the drownings occurred, the Star said.