First Battle of Yeonpyeong The First Battle of Yeonpyeong ( Korean : 제1연평해전 , " Yeonpyeong Haejon " ) took place between the navies of North Korea and South Korea on 15 June 1999 , off the island of Yeonpyeong . Prelude . The battle occurred after North Korea began a sustained campaign to redraw the maritime boundary line – known as the Northern Limit Line ( NLL ) – between the two Koreas . On 6 June 1999 , the state - controlled Korean Central News Agency ( KCNA ) claimed that the " sea boundary line " had been violated by South Korean warships that had illegally trespassed in the North ' s territorial waters . The following day , three North Korean patrol boat s and thirteen fishing boats belonging to the North Korean Navy crossed the NLL off Yeonpyeong . The South Korean Navy responded by sending five fast boats and four patrol ships in a bid to prevent the North Koreans from crossing the NLL . On 8 June , seven North Korean patrol boats and seventeen fishing vessels repeatedly crossed the NLL between 05 : 55 and 23 : 20 local time . Twelve South Korean fast boats and four patrol ships were deployed and South Korean fishing boats were ordered to leave the area . The South Korean military issued a directive ordering a " bold response " to North Korean provocations , while stressing the need to uphold the rules of engagement . The first physical confrontation occurred on 9 June , when six North Korean patrol boats and five fishing boats crossed the NLL again . As on the previous day , the South Koreans deployed twelve patrol boats and four patrol ships . At 06 : 35 , a North Korean patrol boat collided with a South Korean fast boat , causing minor damage . The South Korean Ministry of National Defense issued a statement calling on the North Koreans to desist . Further clashes occurred the following day when South Korean fast boats confronted four North Korean patrol boats that were accompanying a group of twenty fishing boats . The South Korean government decided at this point to use force to oppose further crossings of the NLL . On 11 June , the South Korean Navy began forcibly responding to continued North Korean crossings of the NLL by beginning a " bumping offensive " , using its boats to physically push aside the North Koreans . Four North Korean boats were damaged , two seriously , while three of the South Korean boats suffered damage to their hulls . The North Koreans retaliated on 12 June by attempting their own " bumping offensive " but were outmanoeuvred by the South Koreans . The North Korean Navy deployed three torpedo boat s the next day , prompting a deployment of two " Pohang " - class corvette s by the South Koreans on 14 June . By this time , the North Koreans ' patrol boats had crossed the NLL 52 times and their fishing boats had crossed 62 times . Main clash . The battle began on the morning of 15 June . The North Koreans had twenty fishing boats south of the NLL , which were joined at 08 : 45 by four patrol boats . The patrol boats began attempting to " bump " South Korean fast boats . At 09 : 04 they were reinforced by three North Korean torpedo boats which joined in the " bumping offensive " . The South Koreans again outmanoeuvred the North Koreans and began ramming them , hitting six North Korean vessels in the stern . The North Korean patrol boat PT - 381 found itself being bumped by two South Korean fast craft simultaneously , one hitting it in the stern and the other in the side . At 09 : 28 , the crew of PT - 381 fired machine guns and 25mm cannon at the two South Korean fast craft . The South Koreans retaliated with a 20mm Gatling gun and 40mm and 76mm weapons . During the next fourteen minutes , the South Koreans fired a total of 4 , 584 rounds of ammunition before breaking off the engagement . The battle resulted in the sinking of at least one forty - ton North Korean torpedo boat , severe damage to a 420 - ton patrol craft , crippling of two 215 - ton patrol boats and slight damage to two seventy - ton patrol boats . Official South Korean estimates put the casualties at seventeen to thirty North Korean personnel killed , though unofficial estimates suggested that the figure could have been over 100 . One South Korean patrol ship and four fast craft were damaged and nine sailors were slightly injured . Post - battle . The North Koreans retreated to their side of the NLL by 11 : 00 and ceased crossing the line . Although military tensions on the Korean peninsula escalated for a while as a result of the battle , no further conflict resulted at that time . Despite the severe losses suffered by its navy , the North Korean government claimed victory ; KCNA asserted that " more than ten enemy battleships were either burned or severely damaged and they had no alternative but to flee , taking many dead bodies and remnants with them . " Minor incidents and incursions concerning fishing in the area have since continued , including another naval skirmish in 2002 known as the " Second Battle of Yeonpyeong " and another in the 2009 known as the " Battle of Daecheong " . In November 2010 , North Korea attacked Yeonpyeong itself .