With the outbreak of the Korean War, "Grapple" re-commissioned 26 December 1951 at San Diego, Lt. Roy Coniam in command. After training exercises, she sailed to Pearl Harbor and from there to Japan, reaching Sasebo 8 May 1952. Five days later she sailed for Korea and joined British units of the United Nations Fleet off Daido Ko 17 May. Later she sailed to Ullong Do and was temporarily converted into a floating laboratory as Navy doctors frantically tried to stem a typhoid epidemic sweeping the peninsula.