Climate model simulations of the summer South Asian monsoon predict increased rainfall in response to anthropogenic warming. However, instrumental data show a decline in Indian rainfall in recent decades, underscoring the critical need for additional, independent records of past monsoon variability. Here, we present new reconstructions of annual summer South Asian Monsoon circulation over the past 250 years, based on the geochemical barium‐calcium signature of dust present in Red Sea corals. These records reveal how monsoon circulation has evolved with warming climate and indicate a significant multi‐century long monsoon intensification, with decreased multidecadal variance. Stronger monsoon circulation would have increased the moisture transport from the Arabian Sea and Bay of Bengal over the Indian subcontinent. If these trends continue, the monsoon circulation and associated moisture transport and precipitation will remain strong and stable for several decades. Plain Language Summary Despite the importance of the summer South Asian monsoon in controlling the timing and amount of precipitation delivered to more than a billion people across South Asia, there remains considerable uncertainty in how the monsoon system has changed as climate has warmed over the past couple centuries. Understanding the past behavior of the monsoon system aids in the projection of future monsoon variability and trends. In this paper, we present new, independent reconstructions of South Asian monsoon circulation. These reconstructions are derived from the geochemistry of corals collected from the Red Sea. Winds driven by the South Asian monsoon circulation blow dust from the Tokar Gap region of Sudan, which is deposited on the Red Sea. The dust releases barium to seawater, which is then incorporated into coral skeletons. These records show a multi‐century long trend of increasing monsoon intensity and weakening multidecadal‐scale variability. This suggests that as the climate warmed, the monsoon circulation became stronger and more stable on multidecadal timescales. Stronger monsoon circulation would have increased the moisture transport over the Indian subcontinent, increasing precipitation. If these trends continue, we would expect the monsoon circulation and associated precipitation to remain strong and stable for several decades. Key Points Summer South Asian monsoon circulation is reconstructed from coral geochemistry Reconstructions reveal century‐scale trends of increasing monsoon strength and decreasing decadal‐scale variability Reconstructed trends agree with climate models forced by observed long‐term warming