Dreamworld's parent company Ardent Leisure has been fined A$3.6 million (NZ$3.8 million) over the deaths of four people in 2016.
The operators pleaded guilty to three breaches of workplace health and safety laws at the Gold Coast theme park.
New Zealander Cindy Low, Kate Goodchild, Luke Dorsett and his partner Roozi Araghi died when the Thunder River Rapids Ride malfunctioned and threw them over the raft.
Southport magistrate Pam Dowse sentenced the company on three charges at a hearing in the Gold Coast on Monday.
"The defendant operated the most iconic amusement park in the country," she said, according to the Brisbane Times.
"Complete and blind trust was placed in the defendant by every guest that rode the Thunder River Rapids Ride and those guests were extremely vulnerable."
The maximum penalty for each breach is $1.5 million, meaning Ardent Leisure was facing a maximum penalty of $4.5 million, according to ABC.
The Southport Magistrates Court heard victim impact statements from families of those affected during the incident.
Kim Dorsett, the mother of Luke and Kate, told the court she was shocked when two police officers arrived at her Gold Coast hotel room to tell her the news "no mother should hear".
Her teenage granddaughter Ebony was with Dorsett at court and was on the ride with her mother Kate when the incident occurred.
"Ebony had survived the accident and was hysterical, trying to tell of the events that had taken place that afternoon," Dorsett said, per ABC.
"'I couldn't find Mummy'. These words have become a recurring nightmare. Words that will be with me until I, too, take my last breath."
Ardent Leisure chairperson Dr Gary Weiss and the group's theme parks division CEO John Osbourne said in a statement they apologised "unreservedly for the past circumstances and failures at Dreamworld".
"Ardent accepts responsibility for this tragedy without qualification or reservation," the statement said.
"The Ardent Board and the new Dreamworld leadership team would like to express their deepest sympathies to the families of Roozbeh Araghi, Luke Dorsett, Kate Goodchild and Cindy Low for the enormous loss.
"Today we accept the Court's decision to impose a fine of $3.6 million which is the largest fine in Queensland history for a workplace tragedy."
