BACKGROUND: The rapid rise of non-communicable diseases, particularly type 2 diabetes mellitus (T2DM), poses a significant global public health challenge, with South Asia experiencing an increasingly severe burden. This study aimed to analyse historical trends of T2DM across South Asia from 1990 to 2021 and forecast incidence through 2031. RESEARCH DESIGN AND METHODS: We carried out analysis based on the data from the 2021 Global burden of disease study. Joinpoint regression was used to identify significant changes in trends over time, and ARIMA models were applied to forecast incidence rates. RESULTS: Between 1990 and 2021, the average annual percentage change (AAPC) of age-standardized prevalence rates and incidence rates increased by 2.15 and 1.72 respectively. The age-standardized mortality rate rose more slowly, at 1.05 AAPC, with females experiencing a slightly higher AAPC than males. ARIMA forecasts suggest that by 2031, T2DM incidence rates will continue to rise significantly across all South Asian countries. CONCLUSIONS: This study highlights the need for public health policies focused on preventing obesity, promoting physical activity, and improving healthcare access. It also calls for addressing regional disparities in T2DM prevalence and mortality to better allocate resources and prioritize policies to combat the diabetes epidemic inSouth Asia.