Time runs from appeal or discovering local assets.
The Ontario Court of Appeal has held that the time limit for suing in Ontario on a foreign judgment runs from when it was "discovered" that suing in Ontario was appropriate. In most cases this will be when the final appeal judgment is given or perhaps when the creditor discovers the debtor has assets in Ontario to execute against: Independence Plaza 1 Associates LLC v Figliolini  FICR 8.
A plaintiff obtained judgment in New Jersey, USA in 2013 and an appeal was dismissed in 2014. The plaintiff sued on the judgment in the Ontario Superior Court more than two years after the judgment was given but less than two years after the appeal was dismissed.
The defendant argued that the proceeding was time barred because the two year limitation period under s. 4 of the Limitations Act, 2002 ran from the date of judgment rather than dismissal of the appeal. The trial judge held that time for suing on the foreign judgment was two years from the date the appeal was dismissed, and the defendant appealed.
The answer depended mainly on when a judgment creditor discovers that it would be "appropriate" to sue on the judgment in Ontario. This will usually be when final judgment is given or when the creditor learns that the debtor has assets in Ontario to levy execution against.
The court said a foreign judgment creditor may seek an interim Mareva injunction to freeze exigible assets of the judgment debtor in Ontario before a proceeding on the foreign judgment is commenced in the province and while the foreign appeal process is still running its course.
A foreign judgment debtor may obtain a stay of execution of an Ontario judgment that the creditor obtained after successfully suing on a foreign judgment that is still under appeal.
To sue on a foreign judgment, the creditor must show that the foreign court had jurisdiction and that the judgment is final and for the payment of money (or that it would be appropriate for the Ontario court to recognize it as enforceable within the province even if it is interlocutory or non-monetary).
The foreign judgment debtor is entitled to raise defences to the proceeding, such as fraud, denial of natural justice and public policy.