Tach Duc Thanh Nguyen, 28, Matthew Norman, 19, and Si Yi Chen, 21, were all found guilty of illegally exporting first-class narcotics in an organized way, Denpasar state court judge Istiningsih Rahayu said.
The three sentenced Wednesday, appeared calm when their sentences were read out.
Judge Rahayu said the panel of judges consequently decided to "issue the life sentence to each of the defendants".
The trio, were arrested at the Melasti Hotel at Kuta Beach on the night of April 17 with an alleged stash of 334 grams of heroin.
Police say they also found materials and equipment they claimed would have been used to prepare another drug shipment.
"They were awaiting another delivery of heroin at their hotel," prosecutor Oloan Nainggolan told the court, which was not as crowded as for verdicts delivered for the other six defendants.
The three arrived in Bali on flights on April 6 and 8. Prosecutors allege that 10 days later Nguyen helped ringleaders Myuran Sukumaran and Andrew Chan strap packages of heroin to the bodies of four couriers.
Appeal likely
Mohammad Rifan, one of the trio's lawyers, said they were “disappointed at the verdict."
"We will consult with our clients but our advice is that they should appeal," he told reporters.
The three Australians made no comment to the press.
The verdicts mean that seven members of the Bali Nine group have been given life behind bars, while the two ringleaders Andrew Chan and Myuran Sukumaran received the death penalty, by firing squad, Tuesday.