Seasonal surface freshening of the Makassar Strait, the main conduit of the Indonesian Throughflow (ITF), is a key factor controlling the ITF. Here we present a 262 year reconstruction of seasonal sea‐surface‐salinity variability from 1742 to 2004 Common Era by using coral δ18O records from the central Makassar Strait. Our record reveals persistent seasonal freshening and also years with significant truncations of seasonal freshening that correlate exactly with South Pacific Convergence Zone (SPCZ) zonal events >4000 km to the east. During these events, the SPCZ dramatically rotates ~15° north to near the equator and stronger westward flowing South Pacific boundary currents force higher‐salinity water through the Makassar Strait in February–May halting the normal seasonal freshening in the strait. By these teleconnections, our Makassar coral δ18O series provides the first record of the recurrence interval of these zonal SPCZ events and demonstrates that they have occurred on a semiregular basis since the mid‐1700s. Plain Language Summary The South Pacific Convergence Zone (SPCZ) is a persistent high rainfall band located in the western Pacific and is an important feature of the global hydrologic cycle yet its dynamics and even current position are poorly represented in climate models. Recent studies documented that during some El Niño events, the SPCZ rotates counter clockwise about 15 degrees of latitude north assuming a zonal position on the equator. However, we do not know if these SPCZ zonal events are a new phenomenon. We generated a geochemical record of surface ocean salinity (salt content) from a set of corals 1400 km west of the SPCZ in the central Makassar Strait of Indonesia that has recorded saltier conditions during the SPCZ zonal events back to 1742 A.D. Our unique record indicates that these are regular events happening every 10 to 20 years. The Makassar Strait is the main channel for an ocean current know as the Indonesian Throughflow (ITF), an important current transporting water and heat from the Pacific to the Indian Ocean and then on into the Atlantic. Thus, our coral salinity record indicates that the SPCZ position can act like a switch allowing saltier South Pacific water to flush through the Makassar Strait affecting the ITF. This also suggests that changes in the mean position of the SPCZ will influence the ITF and perhaps global climate. Key Points SPCZ zonal events are regular features of SPCZ variability SPCZ position can influence surface salinity in the Makassar Strait, the main conduit for the Indonesian Throughflow Paleoceanographers need to consider teleconnections and intermittent teleconnections when evaluating paleoclimatic data