Does a non-resident buyer need a Canadian tax number before closing on an Ontario property?

Not necessarily just to complete the purchase itself - closing mechanics do not automatically require a non-resident buyer to already hold a Canadian tax identification number the way, for example, a mortgage application might require certain documentation. What actually drives the need for a number is your future tax situation, since obligations that can arise later - filing a return connected to the Underused Housing Tax if it applies to you, or eventually reporting a future sale of the property as a non-resident - often do require a CRA-issued number, such as an individual tax number, depending on your specific circumstances.

Because the type of number needed and the timing of when to apply for it depend on which future obligations are actually likely to apply to you, this is worth discussing with a lawyer or accountant early in the purchase process rather than treating it as a closing-day requirement or ignoring it entirely until an obligation arises unexpectedly.

Ask your lawyer or accountant early which CRA number, if any, you are likely to need given your specific situation, so you are not scrambling once a filing obligation actually comes due.