Leonardo da Vinci’s proposed underwater breathing device is commonly called a diving suit.
His early-sixteenth-century design included a mask, breathing tubes, and a system intended to keep the diver supplied with air at the surface. The concept was prepared in the context of possible naval operations, including underwater attacks on enemy ships. Leonardo also considered a flexible suit and a means of controlling buoyancy and movement.
The exact construction and operation of the design remain uncertain because Leonardo’s notebooks contain sketches and descriptions rather than a documented full-scale test. Some reconstructions interpret the tubes as connected to floating air containers, while other retellings simplify the design into a modern-looking scuba outfit. Those interpretations should not be treated as proof that it functioned like modern scuba equipment.
Leonardo’s proposal predates self-contained underwater breathing apparatus by centuries. It is best understood as an early conceptual diving system, not as the invention of modern scuba diving.