Bonavista Bay, arm of the Atlantic Ocean, c.40 mi/60 km long and 40 mi/60 km wide, E N.F., E Canada. Irregular and filled with isls. Cape Bonavista, the headland of the Bonavista Peninsula, marks the S entrance to the bay and is the reputed landfall (1497) of John Cabot, the discoverer of N.F. Bonavista is the chief fishing town.