Trinity Bay is a large bay on the northeastern coast of Newfoundland in the Canadian province of Newfoundland and Labrador. The Bay along with Placentia Bay to the southwest define the isthmus of Avalon from which the Avalon Peninsula lies to the east of the main landmass of Newfoundland Island. The maximum depth of the bay is about 580 metres (1,900 ft).
Major fishing communities include Trinity and Heart's Content. The smaller communities in Newfoundland may often be referenced by the Bay in which they are located, e.g.: 'Brownsdale, TB'.