When traveling between the United States, Mexico and Canada, U.S. Legal Permanent Residents, or green card holders, are held to the same requirements as U.S. citizens. There is no special documentation or visa required for green card holders to enter any North American country even if they are citizens of a nation that is required to obtain a visa before entering. A citizen of Brazil is required to obtain a visa before entering Canada, however, a citizen of Brazil who holds an U.S. green card does not need a visa to enter Canada, as the green card acts as his/her visa.
Gather your travel documents to enter Canada. You will need your passport and your green card in order to enter the country. If your green card has expired and you are awaiting its renewal, make sure you have your I-90 Form.
File for a reentry permit if you are intending to stay in Canada for an extended period of time. Green card holders are allowed to travel internationally for periods under one year in length without penalty. Travel to Canada (or anywhere) for a time period between one and two years requires the acquisition of a reentry permit, Form I-131 Application for Travel Document. The form must be filed through the United States Citizenship and Immigration Services (USCIS) prior to travel. Only those who intend extended travel for a particular reason need apply for a reentry permit.
If a green card holder remains in Canada for a period of one year or more without obtaining a reentry permit, he will be striped of his green card and automatically become an illegal immigrant of Canada and subject to deportation.
Enter Canada via land border, plane or by seaport. When leaving Canada to reenter the United States, you will need to have both your passport and your green card available for the border patrol agents to review.