The ROKMC is a branch of the Republic of Korea Navy responsible for amphibious operations,[1] and also functions as a rapid reaction force and a strategic reserve.

On April 15, 1949, the Republic of Korea Marine Corps (ROKMC) was founded at Deoksan airfield in Chinhae with an initial strength of 380 men.

[3]: 24 Following the start of the Korean War on 25 June 1950, the Ko Kil-hun [ko] Unit (Marine Rifle Battalion) landed Gunsan on 16 July and Kim Sung-un [ko] Unit (Marine Rifle Battalion) landed Tongyong peninsula on 17 August where they delayed the advance of the Korean People's Army (KPA) forces, The Marines were rapidly expanded to three battalions and took part in fighting at Mokpo, Changhang, Chindongri, Jinju, Namwon and Masan.

Before the Inchon Landing, ROKMC regiment size unit was formed and attached to USMC 1st Marine Division.

The ROKMC 3rd Battalion was assigned to protect the 5th Marines left flank and capture high ground near Ascom City west of Kimpo.

On the morning of 17 September the ROKMC 3rd Battalion began clearing Ascom City, a two square mile maze of huts in which many KPA had taken shelter.

The Regiment less the 1st and 3rd Battalions was deployed 18 miles (29 km) east of Seoul to block the KPA retreat but encountered only scattered resistance.

Following the attacks by the Chinese People's Volunteer Army (PVA) in the Battle of Chosin Reservoir the Regiment withdrew to Wonsan to cover the evacuation of United Nations Command (UN) Forces.

[3]: 33–5 After a period of rest and refitting, including training by USMC advisers, the Regiment was assigned to the 1st Marine Division in mid-January 1951.

[3]: 39–41  With the PVA offensive blunted by 20 May the UN launched its May–June 1951 counteroffensive and on 22 May the Regiment made its initial advance to take objectives 3 miles (4.8 km) north of the front.

[3]: 39–41 On 4 June 1951 the Regiment was brought out of reserve to join the 1st Marine Division in an assault on the PVA/KPA main line of resistance along a mountain range extending from Yanggu to Hill 1316 (Daeamsan).

Finally on 10 June the Regiment commander Colonel Kim Tae Shik decided to make a night attack on the KPA positions.

Launched at 02:00 on 11 June the attack caught the KPA unprepared and the Marines quickly overran Hill 1122 and the rest of the ridgeline.

[3]: 46–9 Following the Battle of the Punchbowl the fighting stabilized into static warfare with numerous foot patrols far into PVA/KPA territory and company-strength tank-infantry raids.

Throughout the remainder of 1951, the 1st Marine Division continued to occupy the eastern portion of the X Corps defense sector in east-central Korea.

[3]: 49 In early 1952 the ROKMC 2nd Regiment, commanded by Lieutenant Colonel Kim Doo Chan, was organized as were engineer and medical companies.

The regiment was the first unit to move to its new positions along the extreme left flank of the Eighth Army, where it was given the mission of guarding the approaches to Seoul along the Jamestown Line.

On 12–13 April the PVA increased their attacks by fire and infantry probes of the 1st Marine Division sector and on the night of 17 April launched an attack on the ROKMC 1st Regiment positions but this was beaten back with small arms and artillery fire with the ROKMC 1st Regiment losing two dead while the PVA lost 36 killed.

[3]: 57  Following a period of small unit actions along the main line of resistance, starting in August the ROKMC 1st Regiment participated in the Battle of Bunker Hill.

[3]: 61–3 In early May 1953 the ROKMC 1st Regiment went into reserve, returning to the frontline in July when it defended its positions against PVA probes during the Battle of the Berlin Outposts and Boulder City.

In exchange, the United States agreed to reimburse additional military budgets to South Korea to help modernize its armed forces, totaling about a billion dollars.

Their training included a 10 km ruck march in an hour with full combat gear, and carrying a 100 kg IBS(Inflatable Boat Small) overhead.

[4] In November 1987, the Headquarters Republic of Korea Marine Corps was re-established; it was disbanded in October 1973 due to budget constraint.

As a result of this event, the South Korean government cancelled its Military Reform Plan 2020 which was to downsize the number of Marine Corps personnel deployed in North-West islands.

[8] Plan 307 also includes a plan to fortify all 5 islands in the North-West area until 2015 by constructing bunkers for tanks, K-9 Thunder, K-10 ARV and civilians, digging trenches, establishing Guided-Missile unit which is equipped with 60 Spike missiles and 4 launchers,[9][10] deploying the Hostile Artillery Locating System (HALO) which is manufactured by the Selex Galileo company, creating an AH-1S Cobra unit under the 6th Marine Brigade in Baengnyeongdo, increasing size of artillery units in Yeonpyeong from company to battalion which changed their number of K-9 Thunder from 6 to 18,[11] deploying the K-SAM Chunma and the K-136 multiple rocket launcher to North-West islands and increasing numbers of marines in North-West islands by more than 1000.

[22] On 4 September 2017, When South Korean Miniser of National Defense, "Song Young-moo" announced that "Decapitation Unit (참수부대)" would be established in December 2017.

But "Spartan 3000" was a nickname of the ROK Marine Corps Quick Maneuver Force and this unit was already fully formed in March 2016.

Acquisition plans are tied to Army procurement and focus on increasing tactical mobility, firepower, and command and control.

[38] By the end of 2017, ROK Marine Corps forces are to deploy the Bigung (flying arrow) guided rocket system near the Northern Limit Line (NLL) along the western sea border to protect the islands of Baengnyeong and Yeonpyeong from assault by North Korean hovercraft.

The Bigung is a truck-mounted launcher that uses the LOGIR guided rocket, which is 2.75 in (70 mm) in diameter, 1.9 m (6.2 ft) long and weighs 15 kg (33 lb) with a range of 5–8 km (3.1–5.0 mi).