David Campbell, 54, and Tristan Waters, 40, were arrested in January 2018 after a meeting with undercover operatives at a luxury hotel in in the Serbian capital Belgrade, along with a third Australian, Rohan Arnold, who they were accused of conspiring with.
Footage of their arrests reached Australia before they did but the trio were eventually extradited home.
Arnold was jailed in 2020 for a minimum of 19 years and six months after pleading guilty over the import.
Authorities had allegedly found almost a tonne of pure cocaine, worth more than a billion dollars, concealed in steel beams from China inside a shipping container at Sydney's Port Botany in 2017.
Campbell was then told the shipment had been lost after only one of two containers he expected arrived.
The arrests and eventual extraditions came at the end of a globe-trotting undercover police operation where officers posed as criminals who had happened upon the missing container, eventually luring Campbell to New Zealand to try and retrieve it.
The jury was taken through messaging threads from encrypted devices, including one where Campbell used the identity "importer", to support the Crown's circumstantial case
Campbell said at trial he imported steel from China on behalf of his former business mentor Arnold, and was paid in cattle panels.
Arnold had told him there was a "Chinese asset" hidden inside by the time he sought to retrieve the container, however he was unaware it was drugs and the undercover operatives never referred to it as such, Campbell said.
Waters pleaded guilty in the NSW District Court to conspiring to possess the illicit drugs but denied any involvement in its importation.
He did not give evidence but his lawyer David Dalton SC said he was brought in as an outside troubleshooter, merely playing the role of a principal at the meeting in Belgrade, pretending to be a high-ranking "heavy" in an international drug syndicate.
Waters was recorded during the meeting lying about having been stabbed with a screwdriver, which Mr Dalton said was done to bolster his "heavy" character and should cause the jury to doubt other things he said, which prosecutors sought to paint as admissions.
Crown prosecutor Sean Flood highlighted Waters expressing familiarity with other members of the encrypted group chat, whose identities were not known, as evidence his role went beyond hired help at a late stage.
The meeting was to exchange funds before the drugs would change hands in Australia.
Mr Dalton said Waters did not appear in the group chats, or more broadly in the crown case before the attempted possession began.
He was also pretending to rank above Arnold in the syndicate's hierarchy when the pair attended the meeting with undercover operatives in Belgrade while Campbell waited outside with a gun, Mr Dalton said.
On Tuesday the jury found Waters not guilty of conspiring to import along with Campbell.
Campbell pleaded not guilty to both counts but the jury found him guilty of the attempted possession.
He said he was threatened into participating in the attempt to possess the drugs, which the jury was told to disregard if they considered those threats came from people Campbell was voluntarily working with.
A jury of six women and six men retired for about two weeks before reaching verdicts.
The pair are scheduled to be sentenced for the attempted possession on October 19.
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