How long is Canada's coastline?

Canada has the longest coastline of any country in the world at 243,042 kilometres, more than five times the length of the second-longest national coastline (Indonesia at about 54,716 kilometres) and about 11 per cent of the world's total coastline. The figure measures the mainland coast plus the coasts of all islands at a scale of approximately 1:50,000, the standard used by the World Resources Institute. At smaller measurement scales (lower resolution) the length is shorter; at larger scales (higher resolution measuring every fjord and headland) the length would be even greater. This dependence on measurement scale (the coastline paradox) is well-documented in geography.

Canada's coastline borders three oceans. The Arctic Ocean coast (about 162,000 kilometres including the Arctic Archipelago) covers the northern margins of Yukon, the Northwest Territories, and Nunavut, plus all the Arctic Archipelago islands. The Atlantic Ocean coast (about 41,000 kilometres) covers Newfoundland and Labrador, Nova Scotia, New Brunswick, Prince Edward Island, parts of Quebec along the Gulf of St. Lawrence, and the Hudson Bay coast of Quebec, Ontario, Manitoba, and Nunavut. The Pacific Ocean coast (about 27,000 kilometres including all islands) covers British Columbia and southern Yukon.

British Columbia has a coastline of about 25,725 kilometres (more than the entire Canadian Atlantic coast on its own), reflecting the fjord-laced mainland coast and the Vancouver Island, Haida Gwaii, and many smaller offshore island coasts. Newfoundland and Labrador has the second-longest provincial coastline at about 17,500 kilometres, including the rocky Atlantic shore of Newfoundland Island and the Labrador Sea coast. Quebec, Ontario, and Manitoba have substantial coasts on Hudson Bay and James Bay. Saskatchewan and Alberta are the only Canadian provinces or territories with no coastline.

Canada's coastline includes some of the most biologically productive marine ecosystems in the world. The Bay of Fundy on the Atlantic has the highest tides in the world (16 metres at the Minas Basin). The Grand Banks off Newfoundland are one of the world's most productive cold-water fishing grounds. The Salish Sea on the Pacific is shared with the United States and contains some of the most heavily transited marine waters in North America. The Canadian Arctic coast is home to belugas, narwhals, bowhead whales, ringed and bearded seals, walrus, and polar bears. Climate change is rapidly reshaping the Canadian coast through sea-level rise, more intense storms, sea-ice loss, ocean acidification, and changing fish populations. Canada has 5 National Marine Conservation Areas covering more than 124,000 square kilometres of coastal and marine waters, with federal commitments to protect 30 per cent of marine waters by 2030.