The ROK has decided that it needs to keep up with the Kims and develop their own SLBM technology:

The South Korean Military is developing submarine-launched ballistic missiles (SLBMs), a high-ranking military official said.
“On the 3,000-ton Jangbogo-III submarine, which is currently under production, we are installing a vertical launching pad,” said the official, who spoke on the condition of anonymity. SLBMs are fired undersea and are therefore difficult to detect by radar. He added, “The installation of a vertical launching pad indicates that the SLBM is already under development.” The official also went on to say that the SLBM is being developed under the aegis of the Agency of Defense Development and is expected to be completed by 2020.
The South Korean Navy’s arsenal currently includes the submarine-launched cruise missile (SLCM). However, as North Korea’s endeavor to develop SLBM technology has almost reached completion, the need within the South Korean military to initiate a response has become urgent. [Joong Ang Ilbo]
You can read more at the link, but I would think this is another military development by the ROK caused by North Korea that China cannot be too happy about considering its potential implications to deter aggressive behavior by the Chinese regime as well.

Lt. Cdr. Lee Sung-chun, a member of the 20th contingent of the 300-member Cheonghae Unit, lifts his daughter into the air in joy after a ceremony at a naval base in the southeastern port city of Busan on May 20, 2016, to mark the unit’s return from a six-month mission to combat piracy aboard the destroyer Choi Young off the coast of Somalia. (Yonhap)
It seems to me that the ROK Navy does have a point here because if these protesters were conducting illegal actions that caused cost overruns why should the Korean taxpayer be on the hook for this?:

The South Korean Navy is demanding damages from local groups and residents in Jeju Island for “taxpayer losses” incurred by their opposition to the construction of a new naval base.The groups targeted include the village association of Gangjeong in the city of Seogwipo.“On Mar. 28, we filed a suit with Seoul Central District Court for the exercise of indemnity rights for the Jeju multi-purpose port complex,” the Navy announced in a press release on Mar. 29.“The purpose of this exercise of indemnity rights is to hold those responsible accountable for losses in taxpayer money from among the additional costs of 27.5 billion won (US$23.8 million) incurred due to the [14-month] delay in the port’s construction period owing to illegal obstruction of operations,” it added.
The total compensation claim amounted to 3.4 billion won (US$2.9 million) of the additional costs, with the Gangjeong village association listed among the defendants alongside five groups and 117 residents and activities who took action to oppose the naval base construction.Last year, Samsung C&T demanded 36 billion won (US$31.2 million) in compensation from the Navy for delays in the construction schedule; a figure of 27.5 billion won (US$23.8 million) was finally settled on after mediation by the Korean Commercial Arbitration Board. Mediation is currently under way for Daelim Construction’s claim for 23 billion won (US$19.9 million) in compensation. [Hankyoreh]
You can read more at the link.

President Park Geun-hye (C) offers a silent prayer in front of a monument to fallen soldiers killed in North Korea’s 2010 shelling attack on the border island of Yeonpyeong, at a national cemetery in the central city of Daejeon on March 25, 2016, before attending a ceremony to commemorate South Korean soldiers killed in three major clashes with North Korea in the Yellow Sea. The government has designated the fourth Friday of March as the commemoration day for fallen soldiers in those clashes, including the North’s torpedoing of the South Korean Navy corvette Cheonan in 2010, which killed 46 sailors. (Yonhap)

Family members of the 46 South Korean sailors killed in a North Korean torpedo attack in March 2010 offer a silent tribute at the National Cemetery in Daejeon, central South Korea, on March 5, 2016. (Yonhap)

Prime Minister Hwang Kyo-ahn (C, 1st row), Defense Minister Han Min-koo (3rd from L, 1st row) and other participants pose for a photo during a tour of the 7,600-ton Aegis destroyer, the Seoae Ryu Seong-ryong, at the new civilian-military naval base on Jeju Island on Feb. 26, 2016, in this photo released by the Navy. The tour came after a ceremony marking the base’s launch. The base opened 23 years after it was first initiated to serve as docks for warships and cruise ships and to host forces to quickly respond to any hostile activities in nearby waters. The base construction has been opposed for years by local residents and activist groups who cite environmental damage and the buildup of regional military tensions. (Yonhap)

Seok Hae-kyun (front row, 3rd from L), former captain of a South Korean ship hijacked and saved from Somali pirates, poses with naval officials in front of a monument on Jan. 21, 2016, in Busan, southeast of Seoul, that commemorates the successful commando rescue operation five years ago. Seok was the captain of the chemical carrier Samho Jewelry that was attacked by Somali pirates while sailing through the Arabian Sea. He was shot several times by the pirates during the rescue operation. (Yonhap)
Navy Lt. j.g. Chey Min-jung (C), the second daughter of SK Group Chairman Chey Tae-won, salutes during a ceremony at a naval base in the port city of Busan on Dec. 23, 2015, to welcome home the 19th contingent of the 300-strong Cheonghae unit. The unit arrived at the port of Busan after completing a six-month stint in the Gulf of Aden aboard the destroyer, Chungmugong Yi Sun-shin, to combat pirates operating in waters off Somalia. (Yonhap)

South Korean naval destroyer Gang Gam-chan and its sailors are welcomed at a New York port on Nov. 22, 2015 (local time), as they arrive as part of a trip to 15 nations that participated in the 1950-53 Korean War. The 4,400-ton destroyer and a support ship left South Korea on Aug. 27 for the trip to mark the 70th anniversary of Korea’s liberation from Japanese colonial rule and the establishment of the country’s Navy. They head out for Colombia on Nov. 25. (Yonhap)