Though military diving (aka Combat Diving) has been apparent throughout the ages. Alexander the Great made use of divers for scouting harbours and obstacles and some historians argue the vikings also used them. However it is only in the past fifty or so years that it has fully 'come-of-age' and become recognised as a 'secret' weapon in waging war and peace-time operations.

It comes as no surprise to know that almost all of major powers have armies and navies that to one extent or another utilise combat divers in their operations. Notable countries who 'field' some of the best combat divers are the USA, Russia, Great Britain and a handful of other countries on the European continent. Military diving is mostly the realm of a countries Navy although the army and special forces can often wield their own military divers. As a general rule of thumb Navy divers tend operate in the seas, army divers in the lakes and rivers and special forces in them all!

Underwater Transport Military

Military Diving - Missions

The underwater missions undertaken by combat divers can amount to some of the most dangerous. Not only is it likely to involve (in wartime) missions against a hostile enemy, but often the missions themselves can be just as fearsome when contending with the undersea elements.

Sabotaging enemy shipping and harbour facilities - Limpet mine are attached to a ships hull or obstacle. In WW2 the German Battleship Tirpitz was disabled this way.

Mine Clearance and counter-sabotage - This may include checking friendly vessels following a suspected sonar echo which suggests enemy divers.

Plus More...

Source: Military Dive History

Further Resources here.