Canada will introduce a new entry requirement, known as an Electronic Travel Authorization (eTA), for certain international travellers who fly to Canada. Entry requirements for other methods of travel (land, sea) will not change.
Starting on August 1, 2015, travellers will be able to apply for an eTA online. As of March 15, 2016, travellers will need an eTA before they board a flight to Canada.
U.S. citizens do not need an eTA or a visa. However, proper identification must be presented at the border.