St. James City is an unincorporated community and census-designated place (CDP) on Pine Island in Lee County, Florida, United States.

It is part of the Cape Coral-Fort Myers, Florida Metropolitan Statistical Area.

The community is bordered by San Carlos Bay to the south, by Pine Island Sound to the west, by San Carlos Bay, Matlacha Pass, and Pine Island Creek to the east, and by the community of Pine Island Center to the north.

There were 2,921 housing units at an average density of 200.0 per square mile (77.2/km2).

28.1% of all households were made up of individuals, and 18.2% had someone living alone who was 65 years of age or older.