<p>Main objective of the study is to investigate climate-resilient hybrid reinforced soil structures, drawing on findings from instrumented model experiments conducted with an artificial rainfall simulator. Prior to this, no studies have been reported in the literature on monitoring the hydraulic–mechanical responses of unsaturated lateritic soils subjected to different rainfall intensities and durations using instrumented physical model tests. The instrumentation and monitoring system used in this work consisted of suction sensors (SS), volumetric water content sensors (VWS), LVDTs, DIC camera, a data acquisition system, strain gauges (SG), and earth pressure cells (EPC). Suction was completely lost in the GRS reinforced with geogrids during rainfall. In contrast, the GRS reinforced with composite geosynthetic reinforcements retained suction in both the reinforced as well as in the retained zones even after the rainfall event. Following rainfall infiltration, the geogrid-reinforced wall undergone an increase of 61% in facing deformation relative to its state at the end of surcharging, exceeding the serviceability thresholds recommended in design standards. In contrast, the incorporation of composite geogrids significantly improves their suitability, as evidenced by enhanced drainage capabilities, improved interaction at the soil–reinforcement interface, and reduced wall deformations under rainfall infiltration. The findings of this study suggest that current design practices could be significantly improved by integrating considerations of drainage, suction effects, and seasonal variability. Addressing both drainage efficiency and soil–geosynthetic interactions during the design and the construction phase is crucial for enhancing the long-term performance of reinforced soil structures.</p>