
The Democratic Party of Korea held a leadership election on 25 August 2018. It was the first leadership election since the inauguration of President Moon Jae-in. The elected leader was slated to serve a 2-year term.

The 2018 Japan–South Korea radar lock-on dispute is about an incident between a Japanese aircraft and a South Korean vessel. The aircraft was part of the Japan Maritime Self-Defense Force (JMSDF), while the vessel was part of the Republic of Korea Navy (ROKN). The event occurred on 20 December 2018, without the firing of any weapon, and was followed by a large diplomatic dispute between Japan and South Korea.

The 2018 opinion rigging scandal in South Korea is a political scandal that erupted in April 2018 after a group of ardent supporters of the South Korean President Moon Jae-in had been charged with online opinion rigging. The accused suspects were the members of the ruling Democratic Party (DPK). The main perpetrator, as well as the leader of the pro-Moon group, was a well-known power-blogger called "Druking."

The 2018 Seoul mayoral election was held on 13 June 2018 as part of the 7th local elections. Incumbent Park Won-soon was elected for his third consecutive term; the South Korean Public Election Act places a limit of three consecutive terms on holders of the post, so that Park will not be able to run in the next mayoral election.

The 2018 South Korean by-elections was held in South Korea on 13 June 2018, coinciding with the local elections. 12 seats to the National Assembly of South Korea were contested.

The 7th local elections were held in South Korea on 13 June 2018. The election coincided with the by-elections for the vacant seats in the National Assembly. The election was a landslide victory for the Democratic Party of Korea, the ruling party, after two successful summits with the third inter-Korean summit on 27 April and the first North Korea-United States summit in Singapore on 12 June.

The 2017–18 North Korea crisis was a period of heightened tension between North Korea and the United States throughout 2017, which began when North Korea conducted a series of missile and nuclear tests that demonstrated the country's ability to launch ballistic missiles beyond its immediate region and suggested that North Korea's nuclear weapons capability was developing at a faster rate than had been assessed by the U.S. intelligence community.

The April 2018 Inter-Korean summit took place on 27 April 2018 on the South Korean side of the Joint Security Area, between Moon Jae-in, President of South Korea, and Kim Jong-un, Chairman of the Workers' Party of Korea, and Supreme Leader of North Korea. The summit was the third inter-Korean summit – and the first in eleven years. It was also the first time since the end of the Korean War in 1953 that a North Korean leader entered the South's territory; President Moon also briefly crossed into the North's territory.

The May 2018 inter-Korean summit was the second inter-Korean summit in 2018. On 26 May, North Korean state chairman Kim Jong-un and South Korean president Moon Jae-in met again in the joint Security Area, this time on the North Korean side in the Inter-Korean Peace House in the Unification Pavilion. The meeting took two hours, and unlike other summits it had not been publicly announced beforehand. Photos released by South Korea's presidential office showed Moon arriving at the northern side of the Panmunjom truce village and shaking hands with Kim's sister, Kim Yo-jong, before sitting down with Kim for their summit. Moon was accompanied by Suh Hoon, Director of the National Intelligence Service of South Korea, while Kim was joined by Kim Yong-chol, a former military intelligence chief who is now a vice chairman of the North Korean ruling party's central committee tasked with inter-Korean relations. The meeting was largely centered around North Korean leader Kim Jong-un's upcoming summit with US President Donald Trump. Kim and Moon also embraced before Moon returned to South Korea. On 27 May, Moon stated in a public address that he and Kim agreed to meet again at "anytime and anyplace" without any formality and that the North Korean leader once again pledged to denuclearize the Korean Peninsula in accordance with the Panmunjom Declaration.

The Korean Unification Flag is a flag designed to represent all of Korea when North and South Korea participate as one team in sporting events.

The Panmunjom Declaration for Peace, Prosperity and Reunification of the Korean Peninsula was adopted between the Supreme Leader of North Korea, Kim Jong-un, and the President of South Korea, Moon Jae-in, on April 27, 2018, during the 2018 inter-Korean Summit on the South Korean side of the Peace House in the Joint Security Area.

The Unification Pavilion is a venue for peace talks between North and South Korea. The building is situated in the Joint Security Area on the North side of the Military Demarcation Line bisecting the area. Before the Korean War, the village, named Panmunjom, consisted of householders.