Actual deployments began in January 1958, four and a half years after the end of the Korean War, with the introduction of five nuclear weapon systems: the Honest John surface-to-surface missile, the Matador cruise missile, the Atomic-Demolition Munition (ADM) nuclear landmine, and the 280-mm gun and 8-inch (203mm) howitzer.

The Davy Crockett projectile was deployed in South Korea between July 1962 and June 1968. The warhead had selective yields up to 0.25 kilotons. The projectile weighed only 34.5 kg (76 lbs).

Nuclear bombs for fighter bombers arrived in March 1958, followed by three surface-to-surface missile systems (Lacrosse, Davy Crockett, and Sergeant) between July 1960 and September 1963. The dual-mission Nike Hercules anti-air and surface-to-surface missile arrived in January 1961, and finally the 155-mm Howitzer arrived in October 1964. At the peak of this build-up, nearly 950 warheads were deployed in South Korea.

Four of the weapon types only remained deployed for a few years, while the others stayed for decades. The 8-inch Howitzer stayed until late 1991, the only of the weapon to be deployed throughout the entire 33-year period of U.S. nuclear weapons deployment to South Korea. The other weapons that stayed till the end were the air delivered bombs (several different bomb types were deployed over the years, ending with the B61) and the 155-mm Howitzer nuclear artillery.

The nuclear bombs served both a strategic (SIOP) and non-strategic (theater) role. In 1974, according to Pacific Command, four F-4D Phantom jets of the 8th Tactical Fighter Wing (TFW) at Kunsan Air Base were parked at the end of the runway with nuclear bombs under their wings as U.S. Pacific Air Forces' SIOP Quick Reaction Alert commitment. Their targets were probably in China, only 390 km to the west. The 8th TFW also had a non-SIOP role, presumably against targets in North Korea.

Kunsan's SIOP strike role in 1974 formed part of a three-base axis off China together with the 18th Tactical Fighter Wing at Kadena Air Base in Okinawa and the 3rd Tactical Fighter Wing at Clark Air Base in the Philippines. Although only Kunsan had a Quick Reaction Alert role at the time, all three bases had a "major SIOP non-alert role," according to Pacific Command. The 18th TFW SIOP non-alert role is noteworthy because it shows that the United States continued nuclear strike operations from Okinawa after the island was returned to Japanese control and nuclear weapons removed in June 1972. The continued SIOP role at Kadena means that a diplomatic arrangement (agreement) likely existed between the U.S. and Japan for the reintroduction of nuclear bombs to Kadena Air Base in a crisis.

The Lance surface-to-surface missile was also deployed to South Korea but apparently only with conventional warheads. The nuclear warheads were stored in Guam, where the last of 54 W70 warheads arrived at the Naval Magazine on September 30, 1976.

The internal discussions about Lance provide an interesting example of the trade-off between different weapon capabilities. The army recommended deploying Lance to South Korea because of "Korea as the most likely area requiring use of ground nuclear weapons," and because building extra storage on Guam would be expensive. CINCPAC agreed but recommended that the aging Honest John and Nike Hercules systems be withdrawn upon introduction of Lance. The Commander of U.S. Force Korea concurred but stated that it would be unacceptable to withdraw the Nike Hercules because of its unique anti-air capability.

The Joint Chiefs of Staff were concerned that deployment to the Pacific would be delayed by the presidential decision process on whether to also deploy Lance in South Korea, so the Lance warheads were rushed to Guam. By the end of December 1976, according to the U.S. Pacific Command history, all authorized warheads were in place on Guam.

The Lance surface-to-surface missile was deployed to South Korea, but only in a conventional version. The nuclear warheads stranded in Guam.

The Lance deployment coincided with a major review of the security of nuclear weapons storage sites in the Pacific. The review, which also examined diplomatic arrangements for storage in allied countries and the requirements for nuclear weapons in the region, found that security was unsatisfactory, that diplomatic arrangements were inadequate, and that the number of weapons deployed exceed the requirements of the war plans.

As a result, the FY 1977 nuclear weapons deployment plan trimmed the posture, which included removing 140 nuclear weapons from the Philippines, and initiated the withdrawal of the Honest John, Nike Hercules, and Sergeant missile systems from South Korea. In mid-1977, according to CINCPAC, nuclear weapons in South Korea were stored at Camp Ames, Kunsan Air Base, and Osan Air Base. The nuclear weapons storage site at Osan Air base was deactivated in late 1977. This reduction continued over the following years and resulted in the number of nuclear weapons in South Korea dropping from some 540 in 1976 to approximately 150 artillery shells and bombs in 1985. By the time of the Presidential Nuclear Initiative in 1991, roughly 100 warheads remained, all of which had been withdrawn by December 1991.

See also the other Korea sections:

» The withdrawal of U.S. nuclear weapons from South Korea
» U.S. nuclear strike planning against North Korea