Climate change poses significant challenges to sugarcane production in Reunion Island due to rising temperatures and shifting rainfall patterns. This study assessed the island-wide impact of three IPCC climate scenarios (RCP 2.6, 4.5, and 8.5) on sugarcane yield from 2015 to 2100 using the process-based MOSICAS crop model, combined with high-resolution climate projections from Météo France's BRIO project. The objective was to evaluate adaptive strategies through irrigation management and the deployment of drought-tolerant varieties. Results indicate that, although rising temperatures remain within the optimum range for sugarcane photosynthesis (a C4 crop), changes in rainfall distribution led to strong spatial variability in yield responses. At the island scale, average yield changes remain limited (from -4% to +2% depending on the scenario), but regional disparities are significant. On the southern coast, yields are projected to decrease by 16–17% by 2090, while high-altitude eastern areas may benefit from yield increases of 20–39%. Meanwhile, island-wide irrigation water demand is projected to increase by 15% by 2060 and 24% by 2100. Simulations show that expanding irrigation into currently rainfed areas, particularly at higher altitudes in the South and North-East, could significantly reduce the negative impacts of climate change. Fixed irrigation scenarios (10, 15, and 20 mm per week) suggest that even moderate irrigation levels would enhance yields in non-irrigated zones. However, yield gains in already irrigated low-altitude areas may require higher irrigation inputs (=20 mm/week) to maintain productivity. An additional adaptation strategy explored in this study involves the use of more drought-resistant varieties. Through a virtual experiment adjusting key physiological parameters related to water stress sensitivity, eight water-stress-resistant (WSR) varietal classes were simulated. Results indicate that varieties with moderately enhanced drought tolerance (