If you stay longer than 6 months under the eTA program and your stay has not been extended by Citizenship and Immigration Canada (emergency situations only), you will lose your travel authorization and not be able to use the eTA for future trips.
Subsequent trips to Canada will require you to apply for a visa and the probability of this visa being rejected will be high.
Thus, you must ensure that you leave Canada before your allowed stay period expires. If you want to stay longer than your authorized stay, you should apply for an extension at least 30 days before the authorized end of your stay.
Paul is an Australian citizen visiting his girlfriend who is temporarily living in Toronto.
Paul has been on Canadian soil for about 5 months with an eTA and does not want to leave his girlfriend in Toronto. He is thinking of a way to stay longer with her.
The first thing that came to mind was to get out of the country, with a short trip with his girlfriend to the United States and a return to Canada a few days later.
Upon entering the country, the officer sensed Paul’s intentions, partly because his girlfriend had a fixed-term visa and he had a travel authorization instead.
The immigration officer allowed Paul to return on Canadian soil, but he did not reset the 6 months. In two weeks, Paul will have to leave the country or he will be staying illegally.