On September 19, 2025, the Supreme Court of Canada released its long-anticipated decision in Kosicki v. Toronto (City), 2025 SCC 28. The case directly addressed whether private landowners can succeed in adverse possession claims against municipal property that is not a highway or road allowance.

In this case, the subject lands were parkland, but this decision could have an impact on a variety of municipal properties. The ruling provides important clarity for property owners, municipalities, and developers alike.¹

The legal test for adverse possession

In Ontario, adverse possession—often called “squatters’ rights”—is a common law right that is also governed by the Real Property Limitations Act (RPLA). The Court reaffirmed that a party seeking title through adverse possession must demonstrate three key elements, satisfied continuously for at least ten years before the property was brought into the Land Titles System:

  1. Actual possession of the land—open, notorious, exclusive, adverse, peaceful, and continuous use.
  2. Intention to exclude the true owner.
  3. Effective exclusion of the true owner from the property.²

As Justice O’Bonsawin explained, “actual possession is established where the act of possession is open and notorious, adverse, exclusive, peaceful, actual and continuous.”³ When these elements are met, the RPLA extinguishes the true owner’s rights after ten years (ss. 4, 5(1), 15).⁴

An important note is that the 10 years of adverse possession must have run prior to the lands being brought into the Land Titles system.

The Court’s decision

The majority of the Court allowed the appeal, holding that municipal parkland is not immune from adverse possession unless explicitly exempted by statute.

  • The RPLA sets out a closed list of statutory exemptions (waste or vacant Crown land, road allowances, and public highways). Municipal parkland is not included in that closed list.⁵
  • The Court rejected the Ontario Court of Appeal’s attempt to create a “public benefit test,” warning that judicially creating new immunities “would defeat the legislature’s intent.”⁶
  • Since the applicants had satisfied the statutory test and no exemption applied, “the City’s title to the disputed land was extinguished pursuant to s. 15 of the RPLA over four decades ago.”⁷

The applicants were therefore declared the fee simple owners of the disputed land.⁸

By contrast, the dissent would have upheld the Court of Appeal’s presumption that municipal parkland is held for the benefit of the public and is therefore shielded from adverse possession, absent clear municipal acquiescence.⁹

Key takeaways

  1. Legislative supremacy: The Court emphasized that “validly enacted legislation is paramount over the common law.”¹⁰ Only the legislature, not the courts, can expand the categories of public land immune from adverse possession.
  2. Municipal risk: Because municipal parkland is not listed in s. 16 RPLA, municipalities must remain vigilant in monitoring their lands.¹¹
  3. Certainty for landowners: Where possession has been “open, notorious, peaceful, adverse, exclusive, actual and continuous” for ten years, property owners may succeed in establishing adverse possession claims, even against municipalities.¹²
  4. Future claims limited: The Court noted that while matured claims are preserved, reforms such as the expansion of Ontario’s Land Titles System (s. 51(1) LTA) have eliminated most new adverse possession claims that did not vest while the lands were in the Registry System.¹³

Why this matters

This decision provides much-needed clarity in an area long clouded by inconsistent case law. For landowners, it underscores the importance of understanding property boundaries and potential rights to adjoining lands. For municipalities, it highlights the necessity of proactive management to safeguard public assets.

At Gowling WLG, our Real Estate and Municipal Law teams are well-positioned to advise both private clients and public authorities on the implications of Kosicki v. Toronto, including boundary disputes, land use planning, and possessory title claims.

Footnotes

  1. Kosicki v. Toronto (City), 2025 SCC 28 at para 1.
  2. Ibid at para 27.
  3. Ibid at para 34.
  4. Ibid at paras 22–23.
  5. Ibid at paras 36–40.
  6. Ibid at para 72.
  7. Ibid at para 84.
  8. Ibid at para 85.
  9. Ibid (Kasirer J., dissenting) at paras 92–94.
  10. Ibid at para 72.
  11. Ibid at paras 36–41.
  12. Ibid at para 84.
  13. Ibid at paras 54–57.