Over the years, the theme park featured a spherical theatre that showed movies on a huge screen, children's play areas, a revolving concert stage and several pavilions suspended above the water.
The provincial government wants to redevelop Ontario Place to include an elaborate spa operated by a private company, a relocated Ontario Science Centre, revamped play and shoreline areas, a parking facility and a provincial police detachment.
The coalition Ontario Place Protectors challenged the province's Rebuilding Ontario Place Act on the basis that it insulates state action from scrutiny by the courts and therefore violates the Constitution.
The coalition also argued that exemptions from environmental and heritage laws and municipal noise regulations amount to a breach of public trust.
An Ontario judge dismissed the application in 2024 and a challenge of the ruling in the provincial Court of Appeal was also unsuccessful.
Writing on behalf of a unanimous Court of Appeal, Justice Grant Huscroft said there was no doubt that the provincial government's decision to redevelop Ontario Place is strongly opposed by a number of concerned citizens and organizations.
Political opposition to the plan has not swayed the government and the coalition has turned to the court in an effort to stop it, Huscroft said.
"But there is no basis for the court to do so. The court is not an alternative forum for resolving political grievances. The only legitimate question for the court is whether the impugned provisions of ROPA violate the law or the Constitution," he wrote.
"They do not, and the appeal must be dismissed."
In January, the Supreme Court agreed to hear the Ontario Place Protectors' case.
The coalition says provincial superior courts have historical and inherent jurisdiction to review laws and government actions protected under section 96 of the Constitution Act, 1867, and to provide effective remedies when governments do not respect the limits on their powers.
The coalition says the Rebuilding Ontario Place Act's scope is unprecedented and appears to violate section 96 by removing the essential core powers of the courts.
It argues the legislation severely limits or entirely eliminates the ability of courts to hold Crown officials accountable through declaratory actions, damage awards and injunctions when they have acted beyond their powers.
The coalition is also seeking to have the doctrine of public trust acknowledged as an unwritten constitutional principle rooted in English common law and inherited by Canada.
It argues the doctrine of public trust maintains that natural and cultural assets are essential to public welfare and must be safeguarded by the state in its role as trustee.
Margie Zeidler, the daughter of Ontario Place architect Eberhard Zeidler, remembers visiting the park as a child.
"It was extraordinary. It was a public place," she said in an interview. "You could have a picnic in the forest. You could watch films at Cinesphere. You could watch any musical performance at the forum."
Zeidler, a member of the Ontario Place Protectors coalition, says the provincial government's actions have made the fight about more than just the historic theme park. "It became more, not about Ontario Place, but about, wait a minute, what democracy are we living in here?" she said. "I didn't know governments could do that."
In their written submission to the Supreme Court, the Crown and the Ontario attorney general say the case should be dismissed.
The immunity provided by the provincial legislation does not go as far as the coalition alleges, the submission says: "(The act) does not make Ontario Place a lawless zone."
Rather, it immunizes the Crown, its servants and agents from civil causes of action arising from specific circumstances, the submission says.
The Crown and attorney general also urge the court to reject the claim that the legislation is invalid because of the doctrine of public trust.
"The novel doctrine articulated by the Appellant is not an unwritten constitutional principle, and even if such a doctrine existed in law, which is denied, there is no evidence in the record that could warrant applying this far-reaching new doctrine to Ontario Place," the submission says.
The case has attracted submissions from interveners, including several provinces, First Nations, civil liberties groups and environmental organizations.
The Supreme Court often reserves its decisions until a later date, meaning a ruling in the case might not come until next year.
This report by The Canadian Press was first published Oct. 15, 2026.
By Jim Bronskill | Copyright 2026, The Canadian Press. All rights reserved.
