Raids are short-duration attacks on objectives, with the specific understanding that the attacking force will withdraw quickly after achieving the mission objective, or finding they are confronting forces too strong to handle. They may be conducted by conventional or unconventional land forces, ships, submarines, or aircraft, or combinations of them.
They are ways to disrupt enemy communications, damage morale, capture prisoners or material of intelligence significance, or to deny the enemy use of resources. They differ from ambushes in that a raid moves into contact with the enemy, while an ambush waits for the enemy to come to it.
Even when tactically successful, raids can backfire, by alerting the enemy to a weakness in his defenses, or the fact that something not thought critical by the enemy is important to the attacking side. To illustrate the latter, an attack on an out-of-the-way observation post might suggest a major operation, which might be seen by those observers, is planned.
Raids by land forces
In this case, "unconventional" refers to irregular forces, since even conventional force raids often use unusual means of reaching the target, to achieve surprise.
Conventional force raiding
- Makin Raid: Principally to show offensive action early in WWII, a U.S. Marine Corps "Raider" battalion, carried by submarines, attacked Makin Island in the Pacific. While it did capture some documents and destroyed the Japanese garrison, it has not been considered highly successful. At the tactical level, there were considerable problems in small boat movement; several Raiders were stranded and later executed by the Japanese. At the strategic level, it warned the enemy of the vulnerability of a number of islands, which they reinforced.
- Operation BITING was a combined amphibious and airborne raid on Bruneval, France. Its purpose was to capture components of a German radar there for analysis by technical intelligence.
Some raids can be of quite large size, as long as there is no attempt to hold the target. Operation Jubilee, the Allied raid on Dieppe, France was tactically disastrous for the attackers, but taught priceless lessons about what would work and not work in amphibious attack. These lessons shaped the eventual main invasion in the Battle of Normandy.
UW raids can be simply to disrupt an enemy force, to capture usable equipment, for taking prisoners for intelligence exploitation, and destroying installations. Both for attacking strong points at a distance, and for destroying reinforced structures, SF may use missiles, typically derived from antitank weapons.  When the raiding force can access the key target, they often use explosives, manually placed so that a small amount can do maximum damage.
- Simpson's raid on Simpson Harbor
Raids by air forces
Air forces, of course, cannot hold ground, but the sense of raiding emphasizes surprise. A good example was the early 1942 Doolittle Raid by U.S. Army bombers, launched from a Navy aircraft carrier to which they could not return, and attacking multiple minor targets in Japan. The attack was intended principally to benefit U.S. home front morale, but had unexpectedly large impact on Japanese strategy.
Certain targets, such as bridges, historically could be attacked only by manually placed explosives. With the advent of precision-guided munitions, the destructive part of the raid may involve special reconnaissance controlling air or guided missile strikes.
Combined forces raids
Prisoner and hostage recovery is a good example of a combined arms raid; while the main combat will be by ground forces,
- Gourley, Scott (27 April 2007), "Bunker Busters", Special Operations Technology 5 (3)