The history of underwater diving starts with freediving as a widespread means of hunting and gathering, both for food and other valuable resources such as pearls and coral. By classical Greek and Roman times commercial applications such as sponge diving and marine salvage were established. Military diving also has a long history, going back at least as far as the Peloponnesian War, with recreational and sporting applications being a recent development. Technological development in ambient pressure diving started with stone weights (skandalopetra) for fast descent. In the 16th and 17th centuries diving bells became functionally useful when a renewable supply of air could be provided to the diver at depth, and progressed to surface-supplied diving helmets—in effect miniature diving bells covering the diver's head and supplied with compressed air by manually operated pumps—which were improved by attaching a waterproof suit to the helmet and in the early 19th century became the standard diving dress.
Limitations in the mobility of the surface-supplied systems encouraged the development of both open circuit and closed circuit scuba in the 20th century, which allow the diver a much greater autonomy. These also became popular during World War II for clandestine military operations, and post-war for scientific, search and rescue, media diving, recreational and technical diving. The heavy free-flow surface-supplied copper helmets evolved into lightweight demand helmets, which are more economical with breathing gas, which is particularly important for deeper dives and expensive helium based breathing mixtures, and saturation diving reduced the risks of decompression sickness for deep and long exposures.
An alternative approach was the development of the "single atmosphere" or armoured suit, which isolates the diver from the pressure at depth, at the cost of great mechanical complexity and limited dexterity. The technology first became practicable in the middle 20th century. Isolation of the diver from the environment was taken further by the development of remotely operated underwater vehicles in the late 20th century, where the operator controls the ROV from the surface, and autonomous underwater vehicles, which dispense with an operator altogether. All of these modes are still in use and each has a range of applications where it has advantages over the others, though diving bells have largely been relegated to a means of transport for surface-supplied divers. In some cases, combinations are particularly effective, such as the simultaneous use of surface orientated or saturation surface-supplied diving equipment and work or observation class remotely operated vehicles.
Although the pathophysiology of decompression sickness is not yet fully understood, decompression practice has reached a stage where the risk is fairly low, and most incidences are successfully treated by therapeutic recompression and hyperbaric oxygen therapy. Mixed breathing gases are routinely used to reduce the effects of the hyperbaric environment on ambient pressure divers.
The history of underwater diving can also be understood as a history of changing forms of access to the underwater environment. Technological developments progressively extended human capabilities from brief direct immersion to prolonged, autonomous and remotely mediated forms of underwater exploration. This perspective forms part of the concept of "Sub-Oceanic History", proposed by Michael W. Jung, which examines the historical relationship between access, knowledge production and control in the exploration and use of the ocean interior.Jung, Michael W.. Towards a Sub-Oceanic History: From Diving History to an Integrated Conceptual Framework. Zenodo, 2026. https://doi.org/10.5281/zenodo.20504596
Freediving
Underwater diving was practiced in ancient cultures to gather food and other valuable resources such as pearls and precious coral, and later to reclaim sunken valuables, and to help aid military campaigns. Breathhold diving was the only method available, occasionally using reed snorkels in shallow water, and stone weights for deeper dives.
Underwater diving for commercial purposes began in Ancient Greece (500 BC), since both Plato and Homer mention the sponge as being used for bathing. The island of Kalymnos was a main centre of diving for sponges. By using weights (skandalopetra) of as much as to speed the descent, breath-holding divers would descend to depths up to for as much as five minutes to collect sponges. Sponges were not the only valuable harvest to be found on the sea floor; the harvesting of red coral was also quite popular. A variety of valuable shells or fish could be harvested in this way, creating a demand for divers to harvest the treasures of the sea, which could also include the sunken riches of other seafarers.
The Mediterranean Sea had large amounts of sea trade. As a result, there were many shipwrecks, so divers were often hired to salvage whatever they could from the seabed. Divers would swim down to the wreck and choose the pieces to salvage.
Divers were also used in warfare. They could be used for underwater reconnaissance when ships were approaching an enemy harbor, and if underwater defenses were found, the divers would disassemble them if possible. During the Peloponnesian War, divers were used to get past enemy blockades to relay messages and provide supplies to allies or troops that were cut off by the blockade. These divers and swimmers were occasionally used as saboteurs, drilling holes in enemy hulls, cutting ships rigging and mooring lines.
In Japan, the Ama divers began to collect pearls about 2,000 years ago. Free-diving was the primary source of income for many Persian Gulf nationals such as Qataris, Emiratis, Bahrainis, and Kuwaitis. As a result, Qatari, Emirati, and Bahraini heritage promoters have popularized recreational and serious events associated with freediving, underwater equipment, and related activities such as snorkeling.
Diving bells
The diving bell is one of the earliest types of equipment for underwater work and exploration. Its use was first described by Aristotle in the 4th century BC: "...they enable the divers to respire equally well by letting down a cauldron, for this does not fill with water, but retains the air, for it is forced straight down into the water." According to Roger Bacon, Alexander the Great explored the Mediterranean on the authority of Ethicus the astronomer.
Diving bells were developed in the 16th and 17th century as the first significant mechanical aid to underwater diving. They were rigid open-bottomed chambers lowered into the water and ballasted to remain upright and to sink even when full of air.
The first reliably recorded use of a diving bell was by Guglielmo de Lorena in 1535 to explore Caligula's barges in Lake Nemi. In 1616, Franz Kessler built an improved diving bell.
In 1658, Albrecht von Treileben was contracted by King Gustavus Adolphus of Sweden to salvage the warship , which sank outside Stockholm harbor in about of water on its maiden voyage in 1628. Between 1663 and 1665 von Treileben's divers were successful in raising most of the cannon, working from a diving bell with an estimated free air capacity of about for periods of about 15 minutes at a time in dark water with a temperature of about . In late 1686, Sir William Phipps convinced investors to fund an expedition to what is now Haiti and the Dominican Republic to find sunken treasure, despite the location of the shipwreck being based entirely on rumor and speculation. In January 1687, Phipps found the wreck of the Spanish galleon Nuestra Señora de la Concepción off the coast of Santo Domingo. Some sources say they used an inverted container as a diving bell for the salvage operation while others say the crew was assisted by Indian divers in the shallow waters. The operation lasted from February to April 1687 during which time they salvaged jewels, some gold, and 30 tons of silver which, at the time, was worth over £200,000.
In 1691, Edmond Halley completed plans for a greatly improved diving bell, capable of remaining submerged for extended periods of time, and fitted with a window for the purpose of undersea exploration. The atmosphere was replenished by way of weighted barrels of air sent down from the surface. In a demonstration, Halley and five companions dived to in the River Thames, and remained there for over an hour and a half. Improvements made to it over time extended his underwater exposure time to over four hours.
In 1775, Charles Spalding, an Edinburgh confectioner, improved on Edmond Halley's design by adding a system of balance-weights to ease the raising and lowering of the bell, along with a series of ropes for signaling to the surface crew. Spalding and his nephew, Ebenezer Watson, later suffocated off the coast of Dublin in 1783 doing salvage work in a diving bell of Spalding's design.
In 1689, Denis Papin had suggested that the pressure and fresh air inside a diving bell could be maintained by a force pump or bellows. His idea was implemented exactly 100 years later by the engineer John Smeaton, who built the first workable diving air pump in 1789.
Surface-supplied diving equipment
In 1602, the Spanish military engineer Jerónimo de Ayanz y Beaumont developed the first documented diving dress. It was tested the same year in the Pisuerga river (Valladolid, Spain). King Philip the Third attended the demonstration.
In the early 18th century, the Englishman Andrew Becker made a leather-covered diving suit with a windowed helmet. The suit used a system of tubes for inhaling and exhaling, and Becker demonstrated his suit in the River Thames at London, during which he remained submerged for an hour. These suits were of limited use as there was still no practical system for replenishing the air supply during the dive.
Open diving dress
In 1405, Konrad Kyeser described a diving dress made of a leather jacket and metal helmet with two glass windows. The jacket and helmet were lined by sponge to "retain the air" and a leather pipe was connected to a bag of air. A diving suit design was illustrated in a book by Vegetius in 1511. Borelli designed diving equipment that consisted of a metal helmet, a pipe to "regenerate" air, a leather suit, and a means of controlling the diver's buoyancy. In 1690, Thames Divers, a short-lived London diving company, gave public demonstrations of a Vegetius type shallow water diving dress. Karl Heinrich Klingert designed a full diving dress in 1797. This design consisted of a large metal helmet and a similarly large metal belt connected by a leather jacket and pants. This apparatus was successfully demonstrated in the river Oder, but was handicapped by not having a reliable air supply system.
In 1800, Peter Kreeft presented his diving apparatus to the Swedish king, and used it successfully.
In 1819, Augustus Siebe invented an open diving suit which only covered the top portion of the body. The suit included a metal helmet which was riveted to a waterproof jacket that ended below the diver's waist. The suit worked like a diving bell—air pumped into the suit escaped at the bottom edge. The diver was extremely limited in range of motion and had to move about in a more or less upright position. It wasn't until 1837 that Siebe changed the design to a closed system with only the hands left out of the suit with air-tight seals around the wrists.