INTERNATIONAL NEWS - Melina Roberge, 23, and Andre Tamine, 64, had initially denied their roles in the import of 95kg (210lb) of drugs on the MS Sea Princess in 2016.
But they changed their pleas ahead of a trial that was due to start this week, Australian media reported.
A third Canadian, 29-year-old Isabelle Lagacé, was sentenced to jail in November over her part in the crime.
According to authorities, the cocaine had an estimated street value of A$21m (£12m; $17m), making it the largest seizure of its kind on a passenger boat in Australia.
On social media, Roberge and Lagacé had posted images of themselves enjoying what appeared to be a seven-week holiday on a cruise from Southampton.
But when the ship docked in Sydney, police sniffer dogs found 35kg of cocaine inside their shared cabin. A further 60kg was discovered in Tamine's cabin.