Citizens of most countries, not permanent residents of Canada, require a visa when travelling to Canada for a short time, or transiting (layover/change planes) inside Canada. If are visiting Canada Temporarily or transiting, you must apply for a visa prior to your arrival in Canada. In the absence of a Visa, you will not be allowed to enter the country. This visa cannot be obtained upon arrival in Canada. If you are exempt from a visa, you still need an Electronic Travel Authorization (eTA).