The passive spreading of spice anomalies in the ocean by the general circulation and their resurfacing at a remote location is one of the key mechanisms for climate variability teleconnections. The southern subtropical Indian Ocean is characterized by a strong north-south salinity gradient in the upper layer between the fresh Indonesian Throughflow (ITF) waters and the relatively salty subtropical waters. Significant interannual variations of the upper ocean spiciness has been observed in the latitude band of 13-18S, where the water masses from the ITF and the subtropics intersect. In this study, spiciness anomalies (isopycnal temperature/salinity anomalies) in the upper south Indian Ocean during recent decades has been investigated using observations and model outputs to quantify the relative contributions from the ITF and the subtropics. The salinity anomalies along the isopycnals are mainly generated in the eastern Indian Ocean, which is contributed by advection associated the ITF and subtropical gyre. The salinity anomalies are then advected westward by the South Equatorial Current. The salinity anomalies contributed from the ITF advection are mostly due to horizontal salinity gradient variations rather than the ITF speed variation. The mixed layer property variations in the isopycnal outcrop region are mainly responsible for the salinity anomalies contributed from the subtropical gyre advection. These salinity anomalies in the source regions are closely related with the Indo-Pacific climate modes, the ENSO and the Ningaloo Nino.