バラバク海峡
Returning to Brisbane on 8 August 1944, "Darter" cleared on her fourth and last war patrol. She searched the Celebes Sea and South China Sea, returned to Darwin to fuel and make minor repairs on 10 September, and put back to the Celebes Sea. She pulled into Mios Woendi on 27 September for additional fuel, and sailed on 1 October with to patrol the South China Sea in coordination with the forthcoming invasion of Leyte. She attacked a tanker convoy on 12 October, and on 21 October headed with "Dace" for Balabac Strait to watch for Japanese shipping moving to reinforce the Philippines or attack the landing forces.