Generally you do not have to register if you do not carry on business in Canada or your worldwide revenues are $30,000 or less as you are considered to be a small supplier. You can choose to register voluntarily in the following cases:
You may also choose to register voluntarily if you enter into an agreement to supply any of the following:
See How to register a non-resident business if you choose to register voluntarily. If you do so, you have to stay registered for at least one year. You can then claim input tax credits for the GST/HST you pay or owe on Canadian purchases used in your commercial activities. When you register, you have to charge, collect, and remit GST/HST on your taxable sales.