Non-resident owners of real property in Canada within the meaning of the Underused Housing Tax Act S.C. 2022, c.5, s.10 (the UHT), are required to file an annual return in Canada pursuant to the Underused Housing Tax Program. They must file this annual return even if they are entitled to an exemption from the tax as excluded owners within the meaning of the UHT. If they do not file they could be subject to the tax as well as interest and penalties. 

More details can be found at the Government of Canada website.