All three were charged with importing a commercial quantity of cocaine, a charge that carries a maximum sentence of life in jail.
Along the way, the women uploaded several photos of their jaunts to Instagram and Facebook, photos that became fodder to illustrate stories of the sudden change in circumstances for the pair.
They used the 51-day cruise from the United Kingdom through Latin America and then to Australia to transport about AUS $21 million (U.S. $16.5 million) worth of cocaine.
A further 60kg was discovered in Tamine's cabin.
Police announced the seizure with some fanfare.
Police called the drug scheme the work of an worldwide drug syndicate and said the arrests were a joint operation between Australian authorities and the Canada Border Services Agency, along with U.S. Department of Homeland Security Investigations and New Zealand Customs Service. Before arriving in Sydney, they had spent 56 days on the cruise ship travelling through the UK, USA, Bermuda, Columbia, Ecuador and Peru.
Isabelle Lagace, 28, (left) and 23-year-old MÃ©lina Roberge posted selfies to their Instagram account during a luxury cruise aboard the MS Sea Princess from NY via Tahiti to Sydney.
The two women were arrested along with Tamine - a Montreal-based loner with no family.More news: Confirmed - Bulbasaur is the Next Special Pokemon for Community Day #3
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Roberce's cabin mate Isabelle Lagace, a 29-year-old Canadian adult film actress, was previously sentenced to four-and-a-half years in prison on November 3 for her part in smuggling the illegal drugs.
Ms Mathur said that Ms Lagace had admitted at one point that she owned the suitcase in which cocaine was later found.
Former porn star Legace was sentenced to seven-and-a-half- years prison for bringing the drugs into the country, but could be free by 2020.
Crown Prosecutor Lincoln Crowley reportedly told the court, "It is, in effect, a floating warehouse". All three of the cruise tickets for the Canadians were booked through the same travel agency, court heard.
Melina Roberce, 23, has pleaded guilty for her role in smuggling 95kg of cocaine into Sydney.
During Legace's sentencing past year, the NSW District Court heard how she had been told not to worry because a woman her age was unlikely to be stopped by Customs.
Both Tamine and Roberce were expected to stand trial in February before they pleaded guilty to a charge of jointly commissioning the importation of a commercial quantity of border controlled drug, the Daily Telegraph reported. She will be sentenced next month.