Seasonal sea surface salinity (SSS) records can be of great value in reconstructing El Ni¿o/Southern Oscillation (ENSO) variability in the equatorial Western and Central Pacific, a region where ENSO-related evaporation and precipitation (E-P) changes are dramatic. The δ18O values of coral skeleton (δ18Ocoral) reflect seawater δ18O (δ18Oseawater) changes, which in tropical oceans are also generally influenced by E-P changes. Therefore, δ18Ocoral is a good indicator of rainfall and ENSO variability. We present biweekly data from Palau, in the northern part of the Western Pacific Warm Pool, for the period 1998--2000, which indicate a strong quantitative relationship between δ18Ocoral, sea surface temperature, δ18Oseawater and SSS. The coral skeletal δ18O values documented the SSS changes after the 1997--98 El Ni¿o; therefore, δ18Ocoral can be used to estimate paleosalinity changes. However, the slope of the δ18Oseawater - SSS relationship cannot be assumed to be constant throughout the tropics, making site-specific calibrations is essential.