If you have a Green Card in the United States, you will not need a visa to visit Canada by land or sea. If you plan to transit or fly through Canada, however, you will be expected to have an Electronic Travel Authorization (eTA). You will need proof of your status in the United States, such as your valid Green Card and a valid passport.
When you arrive at the Canadian border by transit or plane, a border services officer will verify your eTA. However, if you are traveling to Canada directly from the United States by sea or land, you will only need your Green Card or other proof of your permanent resident status to live legally in the United States.
Canadian Visa Expert is an independently owned immigration service that helps people who want to move to Canada.