The relatively intense boundary currents of the western equatorial Pacific, as well as the western Pacific warm pool, have long been recognized as key components in the global climate system. More recently, the eastern Indian Ocean has been identified as a potential source for climate variability over a larger area (Saji and Yamagata, 2003). These systems are not isolated, however, and Pacific-to-Indian Ocean exchange occurs via the Indonesian throughflow (ITF) (see Gordon, this issue). Understanding this exchange, and the ability to estimate it, are therefore essential for understanding the global climate system. Directly measuring this flow has been challenging. This paper outlines a method to estimate the large-scale oceanic transport in the ITF by using satellite-measured sea level from the TOPEX/Poseidon (T/P) altimeter. The satellite measurements do not directly measure transport, but they comprise a long, almost global, measurement of sea level that may be used to index ITF flow.