Small Island located to the west of South Passage at Truk Lagoon.

This island guarded the strategic southern pass, and was the control center for underwater detection systems. Underwater detection coils were present here, to sense magnetic of passing ships. This coil was 4.5m loops and one 750m x 150m loop, marked by two bouys, connected by cable to Faleu Island. This system was fully implemented by 1943, and remained in operation until surrender.

Two 150mm (5.9") guns were emplaced in open pits to cover the south with concrete ammunition magazines. Also a 1.5m range finder and 90cm searchlight on a 6' tower, with sound loactor. 30 men of the 41st Naval Guard Force were stationed on Faleu. 15 mines were installed on the west side of the island, the other 135 were destroyed in an Allied bombing raid before being installed. Other frame construction buildings included a command post, barracks, revetted generator, shrine, underground water reservoir, latrine, water distillation plant, bathhouses, mess hall and kitchen.

South Pass
The South pass was kept open as a main passage for Japanese shipping. Underwater detection coils located on Faleu sensed magnetic variations to detect the passing of ships. The pass was mined 3,000m inside the lagoon with contact moored mines. Japanese ships would maneuver to a clear channel.