Mevlut Coskun, Paea I Middlemore Tupou and Darcy Jenson were convicted of the shooting death of Zivan Radmanovic, a 32-year-old from Melbourne.
A second man, 34-year-old Sanar Ghanim, was shot and beaten but survived the attack.
Coskun, 22, and Tupou, 27, were sentenced at Denpasar District Court to 16 years in prison and Jenson, 24, was sentenced to 12 years.
Coskun and Tupou argued the shooting death was not intentional and occurred during the chaos of the night.
Radmanovic was in Bali to celebrate the birthday of his wife, Jazmyn Gourdeas, along with her sister and Ghanim, who was her sister's partner.
A coroner found Radmanovic suffered three gunshot wounds and blunt force trauma.
Prosecutors said Jenson organised the attack while the other two carried it out.
Jenson was caught at Jakarta's Soekarno Hatta airport in June as he attempted to leave the country.
Coskun and Tupou were arrested in Singapore and Cambodia with the help of Interpol.
During the trial that began in October, the three men said they were offered money to travel to Bali and frighten Ghanim into repaying a debt.
They said the offer came from an Australian man they refused to identify because they feared for the safety of their families.
Investigators testified the group received instructions from a "Mr X" whose identity was never determined.
The court accepted that the men acted for "a promised payment".
Prosecutors had asked the court to sentence Coskun and Tupou to 18 years imprisonment and 17 years for Jenson.
While the panel of three judges said the defendants caused "deep trauma" to the families of the two victims, Presiding Judge Wayan Suarta noted the defendants had no prior criminal records and were co-operative throughout the investigation and trial.
"They are still young and have the chance to improve themselves in the future," he said, stressing that punishment "is not intended as revenge, nor to degrade their dignity, but as a preventive measure so similar acts do not occur again".
