Do I need to register for HST if I run an online store selling to customers across Canada from Ontario?

If your online store is based in Ontario and sells tangible goods, your HST registration obligation is the same as for any other Ontario business — mandatory once your taxable revenues exceed $30,000. Once registered, the tax you charge depends on where your customer is located (the "place of supply" rules): Ontario customers pay 13% HST, customers in other provinces pay that province's applicable GST/HST rate, and customers outside Canada generally receive the supply at 0% (exports are zero-rated).

Ontario sellers are not required to register for provincial sales tax in other provinces just because they sell goods there — GST/HST is the mechanism for most inter-provincial tax on goods sold by Ontario businesses. Some provinces (like Quebec, Manitoba, Saskatchewan, and British Columbia) have their own provincial sales tax systems with separate registration requirements if you have sufficient presence there, but that is a separate analysis.

For digital products (software, online courses, e-books), the supply rules differ slightly. If you are an Ontario-based seller of digital goods to Canadians, the same $30,000 threshold applies and the destination-based rules still apply for determining the rate.