Giovanni Panerai opened the very first watchmaker's shop in Florence in the 1860s and forged a tight network with only the most prestigious and established Swiss watch manufacturers. He was succeeded by his son, Leon Francesco Panerai, and eventually by his grandson, Guido Panerai in the 1890s. Guido expanded his grandfather's business and turned the focus of the company to making high precision mechanisms and became an official supplier to the Royal Italian Navy.
In the early 1900s, the shop moved to a new location, and that shop near the Duomo of Florence still stands today. During this time, the newly named Officine Panerai successfully delivered its precision optical and mechanical instruments to the Ministry of Defense. By 1910, the company was experimenting with luminous materials using a mix of zinc sulphide and radium bromide, later called “Radiomir.” Guido Panerai applied to have the findings patented in Italy and around the world.
In 1915, the Royal Italian Navy commissioned Panerai to supply precision instruments during the First World War. Panerai crafted unique luminous devices designed to aid in sighting naval guns at night, timing mechanisms, depth gauges and mechanical calculators. By the 1930s, the company was supplying the Navy with underwater instruments, torches, wrist compasses and wrist depth gauges. In 1938, Panerai developed the Radiomir watch, able to withstand extreme conditions. The watch featured large (47 mm in diameter) case, wire loop strap attachments, screw-down crown, luminous dial easily read under waterand a hand-wound mechanical movement supplied by Rolex. The strap was made extra long so it could be worn over a diving suit. In 1956, Panerai created a large Radiomir watch for the Egyptian Navy. The innovative timepiece featured an Angelus movement with 8-day power reserve and a rotating bezel with 5-minute intervals to calculate immersion times.
In the mid 1990s, Panerai crafted Slytech, a special edition watch in honor of actor Sylvester Stallone. Stallone, a great admirer of the watch, commissioned the company to create a special watch to use during the shooting of his movie Daylight. After production, Stallone requested a watch with a white dial, to be named Daylight. Panerai also created a personalized edition of the Mare Nostrum watch. The watches in this series are all engraved with the actor's signature on the back.
In 1998, Panerai introduced their first watches with automatic mechanical movements: the Luminor Submersible professional diver's watch, the Luminor GMT with a second time zone indication and the Luminor Power Reserve. At the turn of the century, the company developed the Luminor Submersible 1000 metres. This professional diver's instrument can withstand a depth of 1000 meters and was designed to meet NIHS (Normes de l'Industrie Horlogère Suisse) specifications for divers’ watches.