An Olympic kayaker and his younger brother, who tried to smuggle hundreds of kilograms of cocaine into Australia, have been sentenced a second time after negotiating "very significantly different" circumstances about their offending.

In 2021, a Supreme Court jury found Nathan and Dru Baggaley guilty of attempting to import a commercial quantity of a border-controlled drug.

They were later sentenced to more than 20 years in jail each. However they both successfully appealed against their verdicts last year.

The brothers were due to face a retrial later this month, but instead pleaded guilty to the same charge.

On Monday they were handed new sentences, with Dru Baggaley, 42, jailed for 15 years and Nathan Baggaley, 48, given a 13-year jail term.

With time already served, both men are now eligible for parole.

Criminality 'very significantly different' after legal negotiations

During their sentencing hearing, Justice Declan Kelly noted the agreed facts provided to him varied "substantially" from what had been found to be factual at their first sentence.

"This is very significantly different," he said.

Commonwealth prosecutor Patrick Wilson told the court this was because "matters were resolved through negotiations" ahead of the second trial.

Mr Wilson told the court that this time the pair had pleaded guilty on a "different basis" to when they pleaded not guilty in 2021, and the previous sentence would be of "no real relevance" to Justice Kelly.

"The basis upon which those pleas have been accepted, they're different to what's been described in the particulars of the first trial and are different to the basis on which they were previously sentenced," he said.

Mr Wilson told the court Dru Baggaley, who had earlier been determined to be a "principal organiser" of the plot, was now being sentenced on the basis there was no evidence he "positively knew" the illicit drug was what he was collecting or how much.

"It could not be said that he knew the precise quantity."

Previously, Nathan Baggaley was found to be "actively involved" in the plan, but Mr Wilson told the court it was now accepted that his involvement was minimal and he had no knowledge the drug was cocaine.

Boat named after Colombian city

The court heard several details remained agreed about what took place before, during and after the attempted importation.

In May 2018, Nathan Baggaley purchased a boat and navigation accessories, including a satellite phone which was operated under the vessel name Medellín.

The following month he registered the boat and had the satellite system professionally installed, along with a wireless router, so he could connect to it to his mobile phone's data.

In the days before the offending in July, "Dru or a person known to him", entered mapping details into the satellite system, and Nathan placed black tape over the top of the boat's registration.

Dru Baggaley and another man, Anthony Draper, then filled more than 20 jerry cans with fuel, before boarding the boat in northern New South Wales.

The pair travelled hundreds of kilometres offshore and met with a large foreign ship with about 20 people of "South American or Colombian appearance" armed with guns onboard.

Dozens of parcels were dropped down to Draper and Baggaley, which contained just over 650 kilograms of cocaine.

This entire interaction was being monitored by Australian authorities, and a navy patrol boat was deployed to pursue Baggaley and Draper.

They threw the haul overboard and were eventually arrested while still on the water.

Nathan Baggaley had driven to the boat ramp and tried to make contact with the satellite phone but received no response.

He was not charged until almost a year later.

Draper received a reduced sentence for his role after he agreed to co-operate at the Baggaley's first trial.

Both brothers had significant criminal histories and previously spent time in jail for serious drug offences.