In January 1942, "Nachi" and "Haguro" covered the landings of Japanese troops in the invasion of the Celebes in the Netherlands East Indies, followed by the invasion of Ambon. In the Battle of the Java Sea, "Nachi", "Haguro" and participated in the destruction of the last remaining Allied fleet units in the Netherlands East Indies. On 27 February, the reconnaissance floatplanes from "Nachi" spotted the Allied fleet, enabling "Haguro" to sink the destroyer with a torpedo and damage with gunfire, and for the destroyer to sink the destroyer . Later that same evening a torpedo from "Nachi" sank the cruiser while several minutes later a torpedo from "Haguro" sank the cruiser . Two days later, on 1 March, "Nachi" and "Haguro" and their accompanying destroyers spotted the damaged "Exeter" as she attempted to escape the Java Sea, and together with the cruisers "Myōkō" and "Ashigara" (and their accompanying destroyers) sank her, along with destroyer . , who was accompanying the two British ships, initially escaped the melee only to be caught and sunk about two hours later by planes from the Japanese carrier "Ryujo".