James Bay (French: Baie James) is a large body of water on the southern end of Hudson Bay in Canada. Both bodies of water extend from the Arctic Ocean. It is the southernmost part of the Arctic Ocean. James Bay borders the provinces of Quebec and Ontario; islands within the bay (the largest of which is Akimiski Island) are part of Nunavut. The James Bay watershed is the site of several major hydroelectric projects, and is also a destination for river-based recreation. Several communities are located near or alongside James Bay, including a number of Aboriginal communities such as the Kashechewan First Nation and nine communities affiliated with the Crees of northern Quebec.
As with the rest of Hudson Bay, the waters of James Bay routinely freeze over in winter, although it is the last to freeze over in winter, and conversely the first to thaw in summer.