RCMP Const. Nicole Hall said shortly before 11:30 p.m. PT the woman was hit by a car on Comox Road, sometimes referred to as Dyke Road.
But it took several hours before someone heard her calls for help.
"She was calling for help just by yelling and it actually took a few hours for her to finally reach the ears of someone ... just someone nearby could hear her calls for help just decided to get on their bicycle and go looking for her and then was able to get medical help," said Hall.
The woman was airlifted from St. Joseph's General Hospital in Comox to a hospital in Victoria. Her name has not been released.
Police closed down several streets in the area and brought in a canine unit and collision analysts for their investigation, but have not released a suspect description.
The area has since been reopened to traffic.