According to Genesis, Noah’s Ark had a door made in its side.
Genesis 6:16 gives construction instructions that include making a door in the side of the ark. The same verse mentions an opening or window and three decks. The door is therefore a stated feature of the vessel, not a detail added only by later paintings or films.
Genesis does not specify the door’s material, shape, hinges, or exact dimensions. It also does not call it a gate or hatch in the wording traditionally translated into English as “door.” Modern retellings may depict large loading ramps or multiple entrances, but those features are reconstructions rather than explicit biblical details.
The side-door detail has also attracted symbolic interpretation in religious commentary. For a factual question about the ark’s construction, however, the direct answer is simply “a door.”