Military deception
This plan, codenamed Operation Downfall, had several components, including the Operation Olympic invasion of the southern Japanese island of Kyushu. The deception created to enable Olympic to succeed, Operation Pastel, would have included false attacks against Japanese held-ports in China, as well as Japanese positions on the island of Formosa. The end of the war following the U.S. atomic bomb attacks on Japan ended the need for a ground invasion or a deception plan, so Pastel was never implemented.

At sea: As a liaison to the British Navy early in the war, actor and U.S. Navy officer Douglas Fairbanks Jr. observed and participated in several raiding parties and diversions on the French coast. Upon returning to the United States, Fairbanks proposed to Ernest King, the Chief of Naval Operations the creation of a unit that would plan and execute diversionary and deception missions. King authorized Fairbanks to recruit 180 officers and 300 enlisted men for the program, which was named Beach Jumpers. There are several stories about how the unit was named; during an interview late in life, Fairbanks said British admiral Louis Mountbatten coined it with the intention of creating a designation that provided cover for the unit's activities by being partly descriptive and partly in code.
On 16 March 1943 Beach Jumper Unit ONE (BJU-1) was commissioned with the mission "To assist and support the operating forces in the conduct of Tactical Cover and Deception in Naval Warfare." Eleven BJUs deployed during the war, and were used in all theaters. The Beach Jumpers raided false landing zones and shore defenses during amphibious attacks, sowing confusion with the enemy about actual landing sites and causing the enemy to defend in the wrong place. To carry out these deceptions, their boats were equipped with two .50 caliber machine guns, 10 window (chaff) rockets, smoke generators, and floating time-delay explosive packs. They were also outfitted with naval balloons and communications and psychological operations equipment, including recorders, speakers, generators, and radio jammers. The balloons included radar reflective strips that when towed would cause Beach Jumper units to appear to enemy radar operators as a larger force than they actually were.
Beach Jumper units created diversionary landings during several battles, including Operation Husky and Operation Dragoon. The Beach Jumpers were inactivated after World War II, but were reconstituted for service during the Korean War and Vietnam War. With the U.S. military creating and fielding an Information Operations capability beginning in the early 1990s, the modern Beach Jumpers exist as part of U.S. Naval Information Forces.

Korean War: In the summer of 1950, the Korean People's Army (KPA) of North Korea attacked South Korea. 140,000 South Korean and allied soldiers were nearly defeated. In August and September 1950, South Korea and its allies waged the Battle of Pusan Perimeter against the KPA and succeeded in establishing a defensive line that prevented the KPA from destroying them.
To enable the counterattack that started with an amphibious landing at Inchon (codenamed Operation Chromite), United Nations (U.N.) forces staged an elaborate deception that made it appear the landing would take place at Gunsan, 105 miles away from the actual landing site at Inchon and closer to the Pusan Perimeter. On 5 September, the U.S. Air Force began attacks on roads and bridges to isolate Gunsan. This was followed by a naval bombardment, which was followed by heavy bombing of military installations in and near the town. These tactics were typical pre-invasion steps, and were intended to cause North Korea to believe Gunsan was the planned U.N. invasion site.
In addition to the aerial and naval bombardment, United States Marine Corps officers briefed their units on the supposed Gunsan landing within earshot of many Koreans, assuming that the information would make its way to KPA leaders through rumors or spies. On the night of 12–13 September, the British Royal Navy landed U.S. Army special operations troops and Royal Marines commandos at Gunsan, making sure that enemy forces noticed their supposed reconnaissance of the area. U.N. forces also conducted rehearsals on the coast of South Korea at several sites with conditions were similar to Inchon. These drills enabled U.N. forces to perfect the timing and actions of the planned Inchon landing while simultaneously confusing the North Koreans as to the actual landing site.
On 15 September, United Nations forces under Douglas MacArthur surprised the KPA with the Inchon landing. In the ensuing Battle of Inchon, the U.N. ended a string of victories by North Korea. The KPA collapsed within a month, and 135,000 KPA troops were taken prisoner.

Cuban Missile Crisis: During the period leading up to the Cuban Missile Crisis of October 1962, Cuba and the Soviet Union employed several deceptive measures to hide their activities. These included the codename for the plan to deploy missiles in Cuba; Anadyr, a Russian town, is associated with the sparsely-populated and inaccessible area of Northeastern Russia and did not suggest an operation in the Caribbean. Soviet soldiers constructed false superstructures to hide the defenses of the ships transporting missiles and launching equipment to Cuba, and placed agricultural equipment and other non-military machinery on deck where it could be seen. Upon arrival, the ships unloaded at eleven different Cuban ports to deceive American surveillance efforts. At the same time, Soviet and Cuban news media reported on the supposedly massive agricultural assistance the Soviets were providing Cuba, which provided a plausible explanation for the activity and equipment that could be observed. The Soviet deception proved highly effective and the missiles were discovered only after they were already operational.

Vietnam War: Both North Vietnam and the forces of South Vietnam and the United States made use of deception during the Vietnam War.

Operation El Paso: As part of Operation El Paso, which took place from May to July 1966, the U.S. 1st Infantry Division deliberately exposed information about a planned resupply and engineer equipment convoy from Minh Than north to An Lộc. Division planners anticipated the enemy response would be an ambush at one of a number of possible locations. As a result, the supposedly lightly armed convoy actually consisted of armored cavalry and infantry. Additionally, 1st ID planners prepared for air assault operations at the most likely ambush sites. Events unfolded as the planners had foreseen, and the Viet Cong ambushed the convoy. The ambush sprang the 1st Infantry Division's trap, and the subsequent Battle of Minh Thanh Road resulted in 50 percent of the Viet Cong regiment becoming casualties.

Operation Bolo: In 1967's Operation Bolo, a United States Air Force unit led by Robin Olds successfully countered the threat posed by Soviet MiG-21 fighter planes operating in North Vietnam.
During bombing missions, unescorted U.S. Republic F-105 Thunderchief fighter-bombers would often be attacked by MiG-21s. Heavily laden with ordnance, the F-105s were no match for the faster MiGs. On occasions when the F-105s were escorted by F-4 Phantom II fighter planes, the MiGs would refuse to engage. In addition, the rules of engagement on the U.S. side prevented attacking the MiGs when they were on the ground. This measure was intended to keep the Soviet Union from becoming further engaged in the conflict by preventing casualties to the Soviet mechanics and technical advisors who were assisting North Vietnam.
To counter the MiG threat, Olds' 8th Fighter Wing prepared its F-4s to display the electronic and radar signatures of F-105s. To create this effect, the 8th Fighter Wing outfitted F-4s with QRC-160 jamming pods, a device used only by F-105s. When they flew the mission, Olds and his fellow pilots assumed the route, elevation, speed, and formation of an F-105 flight. They also staggered the takeoff and arrival times of the F-4s, enabling later-arriving F-4s to prevent the MiGs from landing.
The Bolo deception was executed successfully. The North Vietnamese believed they faced an F-105 flight and dispatched their MiGs. The later-arriving F4s prevented the MiGs from returning to their base. The 8th Fighter Wing destroyed seven MiGs in a matter of minutes, while Olds' fighters sustained no losses. The destruction of half their MiGs and uncertainty about whether future flights observed on radar and electronic sensors were unescorted F-105s or F-4s pretending to be F-105s caused North Vietnam to ground its MiGs. The MiGs failed in their mission of preventing U.S. Operation Rolling Thunder bombing runs over North Vietnam.

Tet Offensive: In 1967, the government and military of North Vietnam began planning for an offensive that would begin in early 1968. The intent within the war's area of operations was to spark an uprising by the Viet Cong and others in South Vietnam who were sympathetic to the government in the north. In a wider sense, North Vietnam hoped the offensive would cause a withdrawal of U.S. troops from South Vietnam by undermining U.S. public confidence in the war.
North Vietnam implemented several deceptive measures to mask preparations for the offensive.