“An anti-suit injunction restrains a party from proceeding with his foreign action. In ordering this type of injunction, the court is exercising its in personam jurisdiction over the party. Shaw v. Shaw, 2007 CarswellOnt 4417 (S.C.), at para. 24. It does not restrain the foreign court from proceeding: Shaw, at para. 24. This type of remedy is available to restrain family law litigants from continuing competing family law proceedings commenced in foreign jurisdictions.
The test that must be met by the moving party seeking an anti-suit injunction has been described as follows:
a. It is preferable (not mandatory) that a foreign proceeding is pending;
b. It is preferable (not mandatory) that the applicant has not obtained a stay from the foreign court already;
c. The domestic court is the “potentially appropriate forum”;
d. The domestic forum has the closest connection to the action and the parties, and no other forum is clearly more appropriate; and
e. There is no injustice to the parties if the forum proceeding does or does not go forward, and an injunction will not deprive the forum plaintiff of advantages in the foreign jurisdiction, which would be an unjust deprivation: Shaw, at para. 21;Borschel v. Borschel, 2020 ONSC 4395, 43 R.F.L. (8th) 366, at para. 93; Bell’O International LLC v. Flooring & Lumber Co., 2001 CarswellOnt 1701 (S.C.), at para. 9, citing Amchem Products Incorporated v. British Columbia (Workers’ Compensation Board), 1993 CanLII 124 (SCC), [1993] 1 S.C.R. 897, at p. 519.
As can be observed, the elements for an anti-suit injunction are similar to the jurisdiction simpliciter and forum non conveniens analysis. If anything, the anti-suit injunction may have a lower threshold than the real and substantial connection test; i.e., the requirement to show the domestic court is the “potentially” appropriate forum and no other forum is “clearly more appropriate”. However, I do not need to determine the relative thresholds for purposes of this motion.”