Electronic Travel Authorization (eTA) allows visa-exempt foreign nationals to travel or transit through Canadian airports. It is electronically linked to the travelling individual’s passport and is valid for up to 5 years. With an eTA you can enter Canada for an unlimited amount of times, if you stay for up to 6 months at a time. For travelling within Canada, an eTA is not required. An eTA by itself cannot guarantee its holder entry to Canada. You will be required to present valid travel documents, such as your passport and other supporting documents.