Leonardo da Vinci designed an early diving suit for divers to breathe and work underwater.
His early-16th-century notes describe equipment including a mask, breathing tubes, and a source of air connected to the surface. The concept was intended for military use, particularly underwater operations against enemy ships. Some versions are associated with a floating bell or air reservoir that would supply breathable air.
The design shows Leonardo thinking about pressure, buoyancy, and the practical problem of supplying air below the waterline. It was not modern scuba equipment: the diver did not carry a compressed-air cylinder on the back, and the historical drawings do not establish that the apparatus was ever successfully built or used.
Leonardo’s diving equipment is also sometimes called an underwater breathing apparatus, but “diving suit” is the standard short description for the covered equipment concept. It should not be confused with a submarine, which carries its occupants inside a vessel, or a diving bell, which provides an air-filled chamber rather than a wearable suit.