Water masses between Mindanao and New Guinea are investigated, using hydrographic data, during two R/V Kaiyo World Ocean Circulation Experiment cruises conducted in October 1992 and February 1994. The analysis of this data indicates that the South Pacific Tropical Water (SPTW), which is formed in the southern hemisphere, reached the area of Morotai Island in 1992 and farther north in 1994. The Antarctic Intermediate Water (AAIW) exists in the southwestern area of the southernmost Philippine Sea. There is northeastward flow between Talaud Islands and Morotai Island, which is probably a part of the retroflection of the Mindanao Current. The remnant of the North Pacific Intermediate Water, advected by the flow from the Celebes Sea, was found in 1992. The New Guinea Coastal Undercurrent, transporting SPTW and AAIW from the southern hemisphere, is divided into at least two parts because the retroflection of the Mindanao Current prevents its shallow part from reaching farther north; the shallow part of SPTW turns eastward as a source water of North Equatorial Countercurrent and retroflects toward the southeast. AAIW and the lower part of SPTW flow northward and seem to be linked with the Mindanao Undercurrent. ¿ American Geophysical Union 1996