Republic of Korea Navy

The Republic of Korea Navy (ROKN; 대한민국 해군; Hanja: 大韓民國 海軍; Revised Romanization: Daehanminguk Haegun), also known as the ROK Navy, is the naval warfare service branch of the South Korean armed forces, responsible for conducting naval operations and amphibious landing operations. The ROK Navy includes the Republic of Korea Marine Corps, which is a quasi-autonomous organization. The ROK Navy is the oldest branch of the South Korean armed forces, and celebrated its 65th anniversary in 2010.

Since the Korean War, the ROK Navy concentrated its efforts to build naval forces to counteract the North Korean navy, which has littoral naval capabilities. As South Korea's economy grew, the ROK Navy was able to build larger and better equipped fleets to deter aggression, to protect national maritime rights and to support the nation's foreign policies. As a part of its mission, the ROK Navy has engaged in several peacekeeping operations since the turn of the 21st century.

The ROK Navy has about 68,000 regular personnel including 27,000 Republic of Korea Marines (as of 2010). There are about 170 commissioned ships (with a total displacement of about 181,000 tons ) in the ROK Navy, including some 20 destroyers and frigates, 12 submarines, 100 corvettes and fast attack craft as of 2011. The naval aviation force consists of about 70 fixed-wing and rotary-wing aircraft. The ROK Marine Corps has about 400 tracked vehicles including self-propelled artillery.

The ROK Navy aims to become a blue-water navy by 2020.

Duties and objectives
"The main duties of the Navy shall be operations on the sea and landing operations, and the Navy shall be formed and equipped for that purpose and shall provide education and training necessary therefor."

- Act on the Organization of National Armed Forces

The objectives of the ROK Navy as maritime forces for the National Security are:
 * Establishing autonomous naval forces to deter war
 * Securing maritime superiority to win war
 * Promoting national interests through protection of maritime activities
 * Enhancing the national prestige through naval presence

Origins
Korea has a long history of naval activity. In the late 4th century during the Three Kingdoms Period, Goguryeo defeated Baekjae, fielding amphibious forces of 40,000 men in the process. In the 9th century, Commissioner Chang Bogo of Unified Silla established a maritime base called Cheonghaejin on an island to foster trading with China and Japan, and to cope with pirates.

In 1380, naval forces of the Goryeo Dynasty defeated 500 invading Japanese pirate vessels by deploying shipboard guns, devised by Choi Moosun. This is reportedly the first use of shipboard guns in naval history. In 1389 and 1419, Korean naval forces invaded Tsushima Island to suppress Japanese piracy. In the early years of the Joseon Dynasty, the naval force reached its peak of 50,000 personnel, in order to combat the ongoing piracy issue.

During the Japanese invasions of Korea (1592–1598), the Korean naval force commanded by Admiral Yi Sunshin, who later became the head of the Navy, cut off the invaders' naval lifeline and defeated the Japanese fleet, reversing the war in favor of Joseon. Admiral Yi is also credited with the creation of the Turtle Ship.

By the end of 19th century, the Joseon Navy had no significant naval force other than coastal defense fortresses. Although there was an attempt to modernize the navy by establishing a royal naval school, the Joseon Navy was brought to an end in 1895. In 1903, the government of the Korean Empire purchased its first modern war ship, the Yangmu. Korean naval tradition was disrupted after Korea was annexed by the Empire of Japan in 1910. During the Japanese occupation period, the Imperial Japanese Navy built a naval base - Chinkai Guard District in southern Korea (at present-day Jinhae).

Founding years and Korean War
Shortly after Korea was liberated from the Empire of Japan on August 15, 1945, Sohn Won-yil, a former merchant mariner and son of the independence activist Sohn Jung-do, led the Maritime Affairs Association, which evolved into the Marine Defense Group on November 11, 1945 (later became Navy Foundation Day) and later became the Korean Coast Guard, which was formed in Jinhae. After the new Republic of Korea government was established on August 15, 1948, the Korean Coast Guard was formally renamed the Republic of Korea Navy, and Sohn became the first Chief of Naval Operations of the ROK Navy on September 5, 1948. On April 15, 1949, the Republic of Korea Marine Corps (ROKMC) was founded in Jinhae. In October 1949, the ROK Navy purchased a 600-ton submarine chaser, the former USS PC-823, on the American civil market with funds raised among its personnel. She was renamed ROKS Baekdusan (PC 701) (PC-701 백두산, named after Baekdu Mountain), and became "the first significant warship of the newly independent nation".

The Korean War started with the North Korean army's surprise attack on Sunday, June 25, 1950. The ROK Navy confronted threats from the North Korean navy: "Perhaps the most aggressive and effective, if smallest, member of the South Korean armed services during the first year of the Korean War was the Republic of Korea Navy (ROKN). At the outset of the conflict, the 6,956-man ROKN, with [33] naval vessels of various types, was outnumbered by the 13,700 men and 110 naval vessels of the North Korean navy." With its UN allies, dominated by U.S. forces, the ROK Navy was able to gain control in the seas surrounding the country. On July 27, 1953, the three year-long war was brought to an end when an armistice agreement was signed. During the war, Australia, Canada, Colombia, Philippines, France, the Netherlands, New Zealand, Thailand, the United Kingdom, and the United States contributed naval vessels as UN allies; Denmark sent the hospital ship Jutlandia.

Commander-in-Chief Republic of Korea Fleet, the highest operational command, was established in September 1953.

Building the Navy
Starting in the 1950s, the ROK Navy built up its surface fleet mainly with older warships transferred from the United States Navy. In May 1963, the ROK Navy acquired its first destroyer ROKS Chungmu (DD 91 and later DD 911), the former USS Erben (DD-631), a Fletcher class destroyer. Starting from 1972, nine former USN Allen M. Sumner class and Gearing class destroyers were transferred and added to the ROK Fleet inventory.

During the Vietnam War, the ROK Navy dispatched a naval transport squadron called Baekgu, which was composed of 3 LSTs and 2 LSMs. The Republic of Korea Marine Corps sent into a combat brigade called Cheongnyong to Vietnam.

On January 19, 1967, ROKS Dangpo (PCEC 56), the former USS Marfa (PCE-842), was sunk by North Korean coastal artillery north of the demarcation line off the east coast of Korea In June 1970, a navy broadcast vessel (ROKS I-2) was captured by North Korean patrol craft in the vicinity of Yeonpyeong Islands in the West Sea (Yellow Sea).

In the 70s, the ROK Navy, through the Park Chung-hee Administration's "Yulgok Plan" (an eight-year national defense plan "to build up self-reliant, national defense capability" ), began to build naval forces with indigenous technology; this initiated the ROK Navy effort to build a fleet of locally built ships. The first 2,000-ton frigate ROKS Ulsan (FF 951) was launched in 1980 and the first 1,000-ton corvette ROKS Pohang (PCC 756) was launched in 1982, both featuring indigenous technology. The ROK Navy continued to carry out other new shipbuilding projects such as mine sweepers, logistic support ships and amphibious landing ships in the 80s and 90s.

In 1973, the Republic of Korea Marine Corps, once a separate branch of the armed forces, became a part of the Navy.

Modernizing the Navy
Since the 90s, the ROK Navy has been steadily upgrading its naval forces. In 1995, Admiral An Pyongtae, the Chief of Naval Operations, presented his plan for the future of the ROK Navy, which included building a blue-water navy.

As a part of a plan to strengthen the surface combatant forces, the ROK Navy launched the lead ship of the Gwanggaeto the Great class destroyer in 1996 to replace the former U.S. Navy destroyers. For building up a submarine force, the ROK Navy purchased its first submarine (other than midget submarines), the Chang Bogo (SS 061), from Howaldtswerke-Deutsche Werft of Germany in 1992. In order to replace its antiquated S-2 Tracker anti-submarine warfare airplanes, South Korea purchased a squadron of P-3C Orion maritime patrol aircraft. These were delivered to the ROK Navy starting in 1995.

Establishment of a regional navy
The ROK Navy continues to put its efforts to build a blue-water navy. In 2001, then-President Kim Dae-jung announced a plan for building up the Strategic Mobile Fleet.

In 2002, the lead ship (ROKS Chungmugong Yi Sunshin (DDH-975)) of the 5,500-ton Chungmugong Yi Sunshin class destroyer was launched. In 2005, the 18,800-ton amphibious landing ship, ROKS Dokdo (LPH 6111) was launched. In 2006, the ROK Navy launched the lead ship (SS 072) of the 1,800-ton Sohn Wonyil class submarine, which was named after the first Chief of Naval Operations, equipped with an Air-Independent Propulsion (AIP) system. In May 2007, the ROK Navy launched the lead ship (DDG 991) of the 11,000-ton Sejong the Great class destroyer, built around the American-made AEGIS combat system and the SPY-1D(v) multi-function phased array radar.

As a part of its mission, the ROK Navy participated in several peacekeeping operations since the turn of the 21st century.

On March 26, 2010, ROKS Cheonan, a Pohang class corvette was sunk by a North Korean torpedo, resulting in death of 46 sailors near Baengnyeong Island, in the vicinity of the Northern Limit Line (NLL).

Command and organization
The Republic of Korea Navy includes the Republic of Korea Navy Headquarters, Republic of Korea Fleet, Republic of Korea Marine Corps, Naval Education and Training Command, Naval Logistics Command, and Naval Academy. The Chief of Naval Operations (CNO) is the highest-ranking officer of the ROK Navy.

Senior leadership
As of November 2011, the following people were in office:
 * Chief of Naval Operations: Admiral Choi Yoon-hee (based in Republic of Korea Navy Headquarters, Gyeryong)
 * Commander-in-Chief Republic of Korea Fleet: Vice Admiral Koo Ok-hyoe (based in Republic of Korea Fleet command headquarters, Busan)
 * Commandant of the Republic of Korea Marine Corps: Lieutenant General Lee Ho-yeon (based in Headquarters Republic of Korea Marine Corps, Hwaseong)
 * Commander Naval Education and Training Command: Vice Admiral Jung Ho-sub (based in Jinhae)
 * Commander Naval Logistics Command: Rear Admiral (Upper Half) Im Jong-cheol (based in Jinhae)
 * Superintendent Republic of Korea Naval Academy: Vice Admiral Sohn Jeong-mok (based in Jinhae)

Republic of Korea Navy Headquarters
The ROK Navy is led by the Chief of Naval Operations (CNO). The Republic of Korea Navy Headquarters located within the Gyeryongdae complex, the tri-service headquarters in Gyeryong, includes the office of the Chief of Naval Operations and various agencies and staff functions. The CNO is a four-star admiral and a member of the Joint Chiefs of Staff. The CNO oversees the administration of recruiting, organizing, training, equipping, supplying, and mobilizing the ROK Navy.

Republic of Korea Fleet
Commander-in-Chief Republic of Korea Fleet (함대사령부; CINCROKFLT) is responsible for naval operations, and based at Busan Naval Operations Base with a command headquarters. CINCROKFLT also serves as Commander Naval Component Command (CNCC) of the ROK-US Combined Forces Command (CFC) in peacetime, or as the Deputy Commander Combined Naval Component Command (DCCNCC) in wartime. The Republic of Korea Fleet has three numbered fleets each assigned to the seas east, west, and south of South Korea:
 * Commander First Fleet (base: Donghae)
 * Commander Second Fleet (base: Pyeongtaek)
 * Incheon Naval Sector Defense Command
 * Commander Third Fleet (base: Mokpo)
 * Jeju Defense Command

For various types of naval operations, the ROK Navy has two surface flotillas, a naval aviation force, a submarine flotilla, special warfare (UDT/SEAL) forces, and a training squadron under the command of the CINCROKFLT:
 * Component Flotilla Five
 * Mine Warfare Squadron 52
 * Amphibious Squadron 53
 * Rescue and service squadron 55
 * Ship Salvage Unit (SSU)
 * Air Wing Six
 * Maritime Task Flotilla Seven
 * Submarine Flotilla Nine
 * Naval Special Warfare Flotilla
 * Maritime Tactical Intelligence Group
 * Training squadron
 * Busan naval base squadron

As a part of "Defense Reform 2020," which was proposed by the Roh Moo-hyun Administration, the ROK Navy has been directed to reform its submarine operations command into a fleet submarine force.

Numbered fleets
The three numbered fleets, each led by a Rear Admiral (Upper Half), are responsible for protecting the green-water around South Korea: The First Fleet is for the eastern naval sector, the Second Fleet is for the western naval sector and the Third Fleet is for the southern naval sector including Jeju Island. Each fleet mainly includes squadrons of patrol forces composed of Kwanggaeto the Great class destroyers, Ulsan class frigates, Pohang class corvettes and Chamsuri class patrol boats.

Mobile Task Flotilla
When taking command of the Navy in 1995, Admiral An Pyongtae, then Chief of Naval Operations, proposed to build a blue-water navy for the Republic of Korea. In the year 2001, President Kim Dae-jung announced a plan for creating a task force called "strategic maneuver fleet" (전략기동함대; Jeollyak Gidong Hamdae), which will "protect national interests in the five oceans and contribute to world peace". As part of the plan, the ROK Navy established one task group, Commander Maritime Task Flotilla Seven on February 1, 2010, which evolved from Commander ASW Squadron 51 of the Component Flotilla Five. The Maritime Task Flotilla is composed of two Sejong the Great class AEGIS guided missile destroyers, and six Chungmugong Yi Sunshin class destroyers. The force is hoped to be able to defend South Korea against any North Korean aggression as well as being able to protect trade routes vital to the ROK. It is also designed to be able to suppress disputes or territorial spats using deterrence and if necessary force. Currently the flotilla is divided into two squadrons stationed at bases in Busan and Jinhae. When the new naval base at Jeju Island is completed in 2014 the ROKN will move newly commissioned vessels to the base to strengthen the fleet. In addition to combat operations the ships of the flotilla performs humanitarian operations: A Chungmugong Yi Sunshin class destroyer of the Task Flotilla is being deployed in response to piracy attacks in shipping lanes off the coast of Somalia.

Naval Education and Training Command
The Naval Education and Training Command is one of the two major shore commands of the ROK Navy responsible for training. It is located in Jinhae. Its primary role is to conduct the initial orientation and basic training for new recruits of the Navy and the Korea Coast Guard. One of the major subordinate units is the Naval War College located in Daejeon.

Naval Logistics Command
The Naval Logistics Command is the other major shore command of the ROK Navy. It also operates the Naval Ship Yard located in Jinhae.

Republic of Korea Naval Academy
The Republic of Korea Naval Academy is a four-year coeducational service academy located in Jinhae. It was established in 1946. Graduates are commissioned as Ensigns in the Navy or Second Lieutenants in the Marine Corps. The Naval Academy also hosts the Officer Candidate School, which provides training to become commissioned officers for civilian college graduates and candidates with military experience.

Location
The ROK Navy operates several naval bases in South Korea: Jinhae, Busan, Donghae, Pyeongtaek, Mokpo, Incheon, Pohang. Naval air stations are in Pohang, Jinhae, and Mokpo. Jinhae has been the major port for the ROK Navy since the establishment of the Korean Coast Guard by hosting vital naval facilities including the Naval Shipyard. Busan has become another major naval base for the CINCROKFLT since its Command Headquarters moved from Jinhae in 2007. Donghae, Pyeongtaek, and Mokpo hosts the command headquarters of the First, Second and the Third Fleet respectively. Incheon hosts a Defense Command under an one-star admiral responsible for littoral waters close to Seoul, the nation's capital. Pohang has a naval base for amphibious forces such as the 1st Marine Division located nearby. The ROK Navy also plans to build a new naval base on the southern coast of Jeju-do for basing a squadron of the Maritime Task Flotilla and two submarine squadrons by 2014. The ROK Navy plans to strengthen its control over the seas around the Korean Peninsula by deploying these forces.

Relationship with the U.S. Navy
South Korea has a joint military partnership with the United States as outlined by the Mutual Defense Treaty signed in 1951. Commander U.S. Seventh Fleet (C7F) is designated as Commander Combined Naval Component Command (CCNCC) "for the defense of the Korean peninsula; in the event of hostilities, all friendly naval forces in the theater would fall under C7F control." The ROK and US Governments have agreed on the transfer of wartime operational control to the South Korean government in 2015.

Commander Naval Forces Korea (CNFK) is a shore command of the United States Navy that serves as the shore support agency for all U.S. Naval activity in South Korea. Commander Fleet Activities Chinhae (CFAC) is a U.S. Naval installation in Jinhae.

Personnel
The ROK Navy has about 68,000 personnel, including the 27,000 members of the ROK Marine Corps (as of 2010). Among these members, about 11 percent of them are commissioned officers and about 32 percent of them are non-commissioned officers (including warrant officers). As a part of "Defense Reform 2020," which was proposed by the Roh Moo-hyun Administration, the ROK Navy has been directed to reduce its manpower to 64,000 sailors, airmen, and Marines.

Military service is mandatory for all South Korean men. In the ROK Navy, all members are volunteers, with enlisted sailors and airmen serving for 26-month periods, and enlisted Marines serving for 24-month periods; commissioned officer, warrant officer, and non-commissioned officer serving longer terms than those of enlisted men, or as career sailor, airmen, and Marines. In the year 2001, six female ensigns, who had become commissioned officers through the officer candidate school, were assigned to serve on surface ships of the ROK Navy, for the first time ever.

Commissioned officers
There are several paths to becoming a commissioned officer in the ROK Navy, including the Naval Academy, Officer Candidate School (OCS), and Naval Reserve Officer Training Corps (NROTC). Officer Candidate School, located at the Naval Academy, Jinhae, provides training for candidates with current or prior enlisted experience in the military and civilian college graduates, which take majority in OCS.

Warrant officers
Following the traditions of the British Royal Navy the warrant officer rank in the South Korean armed forces falls in between that of non-commissioned and commissioned officers. In the ROK Navy, warrant officers are mostly former non-commissioned officers who had earned the rating of Wonsa (Master Chief Petty Officer) and who had been selected for and completed a warrant officer candidate program. Another route to becoming a naval warrant officer is to complete a naval aviation warrant officer candidate program. Warrant officers generally mess in the wardroom with commissioned officers.

Petty officers
Petty officers originate from a petty officer candidate program. In the ROK Navy, personnel with ranks of Hasa through Wonsa are considered petty officers (i.e. non-commissioned officers) while those at Sangsa and Wonsa are further referred to as “CPO” (chief petty officer) collectively. There are the appointments of Juim Wonsa and Juim Sangsa equivalent to that of the U.S. Navy's Command Master Chief Petty Officer (CMCPO). The positions are filled by senior Wonsa and  Sangsa respectively and unlike their U.S. Navy counterparts, the ROK Navy Juim Wonsa and Juim Sangsa wear the same standard rate insignia of Wonsa or  Sangsa and only wear a special identification badge. Every ROK Navy establishment and ship has either Juim Wonsa or Juim Sangsa. Petty officers wear a combination cap with a white cover and a gold chinstrap.

Enlisted
In the ROK Navy, enlisted sailors are referred to as "Subyeong" (수병; 水兵). Normally the enlisted sailors serve in the Navy for 23 months; after this, most of them are transferred from active duty to the naval reserve.

Ranks and rates
In the ROK Navy, as in the rest of the ROK Armed Forces, ranks fall into one of four categories: commissioned officer, warrant officer, non-commissioned officer (petty officer), and enlisted, in decreasing order of authority. Commissioned officer ranks are subdivided into "Janggwan"-level officers (flag officers), "Yeonggawan"-level officers (Lieutenant Commander through Captain), and "Wigwan"-level officers (Ensign through Lieutenant). All three branches – the Army, the Navy, and the Air Force) of the ROK Armed Forces share the same names of ranks as written in Hangul.

¹: No one held the rank of Wonsu in the history of the ROK Armed Forces yet. ²: Senior Captains in command of Squadrons can be referred to as “Commodore” verbally and in correspondence as in the U.S. Navy.

Naval engagements of the ROK Navy

 * Battle of Haeju
 * Gangneung Infiltration
 * Battle of Yosu
 * First Battle of Yeonpyeong
 * Second Battle of Yeonpyeong
 * Battle of Daecheong

Major international activities
The ROK Navy frequently participates in multinational exercises and international activities. Also it has engaged in several peacekeeping operations since the turn of the 21st century.


 * Pacific Reach: The ROK Navy has participated in the biannual submarine rescue exercise since 2000. In 2004, the ROK Navy hosted the exercise, which was the first multinational naval exercise the ROK Navy ever hosted.
 * RIMPAC: The ROK Naval forces have participated in the biannual multilateral naval exercise since 1990.
 * ROK-US combined amphibious landing exercise: The ROK Navy and ROKMC together with the U.S. Navy and U.S. Marine Corps conduct the exercise annually in Korea.
 * ROKN-JMSDF SAREX: The ROK Navy and Japan Maritime Self Defense Force (JMSDF) conducted the search and rescue exercise biannually since 1999.
 * WP MCMEX/DIVEX: The mine warfare forces of the ROK Navy have participated in the Western Pacific Mine Counter Measure Exercise/Diving Exercise since 2004.
 * Cruise Training: Since 1954, the ROK Navy has conducted the annual oceangoing training with the fourth year midshipmen (naval cadets) of the Naval Academy to provide on the job training before commissioning them and to foster relations with other navies around the world.
 * Navy to Navy Talks: The ROK Navy holds regular naval conferences with its counterparts of Germany, Indonesia, Japan, Malaysia, Singapore, Thailand, Turkey, the United Kingdom, and United States.
 * Cobra Gold: Together with the ROK Marines, ROKS Seonginbong (LST 685) had participated in Cobra Gold 2010.

Anti-piracy operations
In March 2009, the ROK Navy deployed the Cheonghae task group in response to piracy attacks in shipping lanes off the coast of Somalia. This task group is composed of a Chungmugong Yi Sunshin class destroyer and about 30 naval special warfare personnel. The group operates as part of the multinational task force, Combined Task Force 151 of Combined Maritime Forces (CMF). The ROK Navy has dispatched five warships to the mission area under the name of Cheonghae task group. As of September 2010, ROKS Wang Geon (DDH 978) is carrying out the mission in the area. On January 21, 2011 South Korean naval commandos carried out Operation Dawn of Gulf of Aden, an operation to rescue the crew of the hijacked MV Samho Jewelry and succeed in rescuing the crew and killing or capturing all of the pirates on board.

International fleet review
In October 1998, the ROK Navy hosted its first international fleet review in commemoration of the 50th anniversary of the Republic of Korea and its armed forces off coast of Busan and Jinhae. 21 ships from 11 countries (Australia, Bangladesh, France, India, Indonesia, Japan, New Zealand, Philippines, Singapore, United Kingdom, United States) participated in the fleet review as well as 34 ships and 15 aircraft from South Korea. The ROK Navy hosted its second international fleet review off coast of Busan in October 2008 to celebrate the 60th anniversary of the South Korean government. 22 ships from 11 countries (Australia, Canada, China, India, Indonesia, Japan, Russia, Singapore, Thailand, United Kingdom, United States) participated in the fleet review as well as 33 ships and 27 aircraft from South Korea.

The Cruise Training Unit – ROKS Kwaggaeto the Great (DDH 971), ROKS Jeju (FF 958) and ROKS Cheonji (AOE 57) participated in International Fleet Review 2002 commemorating the 50th anniversary of JMSDF in Tokyo Bay. The Cruise Training Fleet – ROKS Chungmugong Yi Sunshin (DDH 975) and ROKS Cheonji (AOE 57) - visited the United Kingdom in order to take part in the International Fleet Review for Trafalgar 200 in 2005. In April 2009, ROKS Dokdo (LPH 6111) and ROKS Kang Gamchan (DDH 979) attended an international fleet review to celebrate the 60th anniversary of the founding of the Chinese People's Liberation Army (PLA) Navy in Qingdao. In August 2009, the Cruise Training Flotilla – ROKS Choi Young (DDH 981) and ROKS Daecheong (AOE 58) participated in the Indonesian International Fleet Review, which commemorates the 64th anniversary of Indonesian independence.

Equipment
There are about 170 commissioned ships (with a total displacement of about 181,000 tons) in the ROK Navy, including some 20 destroyers and frigates, 12 submarines, 100 corvettes and fast attack craft as of 2011. The naval aviation force consists of about 70 fixed-wing and rotary-wing aircraft.

Ships


The ROK Navy employs the U.S. Navy-style letter based hull classification symbols to designate the types of its ships and hull numbers to uniquely identify its vessels (e.g. DDH 975). The names are that of the historical figures, provinces, cities, counties, peaks, lakes, islands, and birds. The Chief of Naval Operations selects the names of ships.

There are four ship ratings. A first-rate ship (DDG, DDH, Sohn Won-yil class SS, LPH, MLS, AOE, and ARS) is commanded by a captain; a second-rate ship (FF, SS, PCC, LST, and ATS) by a commander; a third-rate ship (SSM, PKG, MSH, and MHC) by a lieutenant commander; and a fourth-rate (PKM and LSF) is commanded by a lieutenant.

Major commissioned ships
The ship prefix for all the commissioned ROK Navy ship is ROKS (Republic of Korea Ship) when the names of ships are written in English.

Surface combatants (destroyers and frigates)

 * Sejong the Great class (DDG: Destroyer Guided-missile; 3 in service)
 * Chungmugong Yi Sun-sin class (DDH: Destroyer Helicopter; 6 in service)
 * Kwanggaeto the Great class (DDH; 3 in service)
 * Ulsan class (FF: Frigate; 9 in service)
 * Incheon class (FF: Frigate; 1 in service)

Submarines

 * Son Won-il class (SS: Submarine; 3 in service)
 * Chang Bogo class (SS: Submarine; 9 in service)
 * Dolgorae class (SSM: Midget Submarine; 2 in service)

Patrol ships (corvettes and patrol craft)

 * Pohang class (PCC: Patrol Combat Corvette; 21 in service)
 * Yoon Youngha class (PKG: Patrol Killer Guided-missile; 9 in service)
 * Chamsuri class (PKM: Patrol Killer Medium; 75 in service)

Amphibious warfare ships

 * Dokdo class (LPH: Landing Transport Helicopter; 1 in service)
 * Gojunbong class (LST: Landing Ship Tank; 4 in service)
 * Solgae 621 class (LSF: Landing Ship Fast; (Project 12061E Murena-E); transferred from Russia; 3 in service)
 * Solgae 631 class (LSF; aka LSF-II; 2 in service)
 * Mulgae class (LCU: Landing Craft Utility; less than 10 in service)

Mine warfare ships

 * Wonsan class (MLS: Minelayer Ship; 1 in service)
 * Yangyang class (MSH: Minesweeper Hunter; 3 in service)
 * Ganggyeong class (MHC: Minehunter Coastal; 6 in service)

Auxiliary ships

 * Cheonji class (AOE: Fast Combat Support Ship; 3 in service)
 * Cheonghaejin class (ASR: Submarine Rescue Ship; 1 in service)
 * Pyeongtaek class (ATS: Salvage and Rescue Ship; ex-USN Edenton-class salvage and rescue ship class; 2 in service)
 * Sinsegi class (AGS: Surveying Ship; 1 in service)
 * Sincheonji class (AGS; 1 in service)
 * Dadohae class (ASL: Midget-submarine Tender; 1 in service)

Ships under construction

 * Son Won-il class (SS; 9 in this class: 3 in service; 1 launched; 4 under construction; 1 more planned)
 * Yoon Youngha class (PKG; 18 in this class: 9 in service; 9 more planned)
 * Incheon class (FFG; 18~24 in this class: 1 in service; 1 launched; 4 under construction; 10~18 more planned)
 * Tongyeong class (ATS; 2 in this class: 1 launched; 1 more planned)
 * Cheonwangbong class (LST; 4 in this class: 1 launched; 3 more planned)

Aircraft
Commander Air Wing Six is the name of the ROK Navy that is responsible for all of its aircraft. This Air Wing's operational headquarters is located in Pohang, and its naval air stations are Pohang (K-3), Jinhae (K-10), and Mokpo (K-15). Air Wing Six has about 20 fixed-wing and 50 rotary-wing aircraft as of 2011.

Ships

 * Korean Submarine (KSS) program

The KSS program was a three-phased project to build up the ROK Navy's submarine forces. Before the KSS program, the submarine fleet of the ROK Navy consisted of midget submarines, such as the Dolgorae class submarine and SX 756 Dolphin class submarine, which had limited capabilities for inshore operations.

Through the first phase, KSS-I, the ROK Navy acquired nine 1,200-ton Chang Bo-go class submarines. For the second phase, KSS-II, the ROK Navy plans to acquire nine 1,800-ton Type 214 submarines with Air-Independent propulsion (AIP) system; the lead ship of her class, the Sohn Won-yil (SS 072) was launched at a shipyard of Hyundai Heavy Industries on June 9, 2006. In June 2007, the ROK Navy launched its second 1,800-ton submarine named Jeong Ji, after a military general of the Goryeo Kingdom who defeated Japanese invaders. The Type 214 submarine is expected to play a key role in safeguarding the country's maritime interests as a part of the Navy's Mobile Flotilla. The third phase of the program, KSS-III is scheduled to begin in 2007 and to build the lead ship of her class in 2017. A total of nine 3,000-ton KSS-III submarines are expected to be built in South Korea with indigenous technologies (i.e. not going under license as the previous KSS-I and KSS-II submarines).


 * Korean Destroyer Experimental (KDX) program

Korean experimental destroyer program is a three-phased program to modernize the surface fleet by developing and constructing new destroyers for the ROK Navy with advanced combat systems and weaponry. The outcomes of this program include the Kwanggaeto the Great-class destroyers, which are the first ROK destroyers to be armed with surface-to-air missiles; the Chungmugong Yi Sunshin-class ASW destroyers; and the powerful King Sejong the Great-class destroyers, which are equipped with the sophisticated AEGIS combat system for air-defense and anti-missile operations. These new destroyers replaced antiquated destroyers that had been transferred from the U.S. Navy decades ago.

In October 2009, the ROK Navy announced plans to build and commission six destroyers of 5,600-ton empty displacement with the AEGIS system (the KDX-II A destroyers) from 2019 to 2026 for beefing up the Maritime Task Flotilla.


 * Frigate Experimental (FFX)

The FFX project aims to replace the Ulsan class frigates and Donghae/Pohang class corvettes with new 2,300-ton frigates. The total number of the ships to be built is 20 to 24 by 2020 and the first batch of six new frigates are planned to be commissioned by 2015, and another fourteen commissioned by 2018. Hyundai Heavy Industries will build the lead ship that is planned to enter service in 2011. These frigates will be armed with the American-made Phalanx CIWS system and the rolling airframe missile system, and they will each carry a Westland Lynx anti-submarine warfare helicopter.


 * Patrol Killer Experimental (PKX)

Through the PKX program, the ROK Navy plans to build a feet of a next generation patrol craft with Cooperative Engagement Capability and enhanced weaponry such as 76 mm guns and the KSSM anti-ship missiles. There are two variations of Geomdoksuri class patrol craft: Geomdoksuri-A and Geomdoksuri-B. The Geomdoksuri-A will be a 570-ton patrol craft with anti-ship missiles; Geomdoksuri-B will be a 300-ton patrol craft serving as the platform design for the Geomdoksuri-A variation. It is speculated that 34 Geomdoksuri-As and 18 Geomdoksuri-Bs are planned. The first batch of nine Geomdoksuri-As are expected to enter in service by 2015 and to replace the aging Chamsuri class patrol craft.

On 28 June 2007, the Yoon Young-ha (PKG 711), the lead ship of her class, was launched at the shipyard of Hanjin Heavy Industries in Busan. She is scheduled to be delivered to the South Korean navy in 2008.


 * Landing Platform Experimental (LPX)

The LPX project was the ROK Navy's new amphibious landing ship project for which Hanjin Heavy Industries & Constructions Co. has provided the general design package. The ROK Navy's requirements for the new amphibious landing ships were to enhance Korea's current amphibious operation capability, both in terms of assault and military operations other than war (MOOTW) type operations.

On 12 July 2005, ROKS Dokdo (LPH 6111), the lead ship of her class, was launched at the shipyard of Hanjin Heavy Industries in Busan. She was delivered to the South Korean navy in July, 2007. The first air cushion landing craft (ROKS LSF 631) of LSF-II project was delivered for ROKS Dokdo in April, 2007.

In October 2009, the ROKN revealed that it plans to commission a new 14,500-ton (full displacement 18,800 tons) LPX around 2018.

The ROK Navy plans to commission four new amphibious ships of 4,500-ton empty displacement between 2014 and 2017.
 * LST-II project

The ROKN plans to commission an uncertain number of 12,000-ton fast combat support ships (AOE) around 2017 to relieve the 9,000-ton Cheonji class ships.
 * AOE-II Project

Through ATS-II project, the ROKN will replace the two ex-USN Beaufort class ships with two locally built 3500-ton salvage and rescue ships.
 * ATS-II project

The ROK Navy plans to commission a new 4,500-ton training ship (ATX) for midshipmen and officer candidates around 2015.
 * Training Ship Experimental (ATX)

The ROKN plans to build and commission an uncertain number of minelayer ships similar to ROKS Wonsan (MLS 560).
 * MLS-II Project

The ROKN plans to build and commission an uncertain number of mine countermeasure ships similar to the Yangyang class.
 * MSH Phase 2

The ROKN believes it can deploy two light aircraft carriers by 2036. They will be used to keep up with rapid Chinese and Japanese naval developments, expand the country's blue-water capability, and assist international peacekeeping operations. There are no fixed requirements currently, but an interim feasibility study is exploring ways to use light carriers over the next two decades. They can equip the second Dokdo-class amphibious assault ships with a ski ramp to operate short take-off and vertical landing aircraft. The Navy could acquire STOVL jets from the U.S., U.K., or Spain and deploy the ship with a ski ramp by 2019. The ROKN could also build a ship similar to the Spanish ship Juan Carlos I (L61) by 2019. Between 2028 and 2036, the Navy plans to build two 30,000 ton-class light aircraft carriers. The carriers are believed to have similar specifications to the Italian aircraft carrier Cavour (550) which carries around 30 aircraft.
 * Light Aircraft Carriers

Aircraft
The ROK Navy had acquired eight P-3C aircraft through the maritime patrol aircraft program phase I. Eight more ex-USN P-3CK maritime patrol aircraft had been delivered to the ROK Navy by 2010 after undergoing extensive refubishment and modernization. In May 2013 it was announced that DAPA was commencing a 1 trillion won ($900 million) procurement program to acquire up to 20 new anti-submarine warfare aircraft to replace the existing fleet of 16 P-3Cs. Possible candidates include the C-295 MPA, P-8 Poseidon and the SC-130J Sea Hercules.
 * Maritime patrol aircraft program phase II

The ROK Navy had planned to acquire new mine countermeasure helicopters by 2012 with a budget of 480 billion won. AgustaWestland EH-101, NHIndustries NH-90, and Sikorsky MH-60S were being considered as possible candidates for the acquisition program before it decided to hold the project due to global financial crisis that hit the world in 2008.
 * Mine countermeasure helicopter program