Do I need a Canadian agent to help file a section 216 return if I no longer live in Canada?

Filing a section 216 return itself doesn't legally require you to have a Canadian agent, but in practice, most non-resident landlords end up needing one, particularly if they also want to reduce withholding during the year through an NR6 arrangement rather than just reconciling everything after the fact. Someone has to be responsible, on the ground in Canada, for withholding and remitting tax on the rent as it's collected, communicating with tenants or a property manager, and handling notices from CRA, a role that's difficult to manage effectively from another country.

A Canadian resident agent, often the property manager or a person specifically appointed for this role, typically handles these administrative and remittance functions, and CRA's guidance is generally built around the assumption that a non-resident landlord has one in place. Without an agent, coordinating the mechanics of withholding, remittance, and responding to CRA correspondence becomes considerably harder.

Because getting the agent relationship set up properly, with clear responsibilities for withholding and remittance, affects both your compliance and your ability to take advantage of reduced withholding during the year, this is worth arranging before you actually start renting out the property rather than after problems come up.