The South American hydroclimate encompasses a wide range of regimes shaped by complex interactions among the Amazon, the Andes Cordillera, and large-scale atmospheric circulation and oceanic variability. This diversity presents unique opportunities to advance hydrometeorological science, while posing significant challenges for understanding, monitoring, predicting, and managing water resources in a changing climate. Advances in Earth observation, remote sensing, artificial intelligence, and numerical modeling are improving our ability to observe, model, and forecast these processes across spatiotemporal scales. This session brings together researchers and practitioners across climatology, meteorology, hydrology, hydroclimatology, water resources, environmental risks, and climate services to showcase recent research advances, experiences, challenges, and opportunities in South America. We invite contributions in four areas: (1) Process understanding: hydroclimatic processes, conceptual and physically based modeling, AI-driven approaches and hypothesis testing locally and across large scales as well as under past and future climate conditions; (2) Monitoring: in situ observations, remote sensing, and low-cost innovative monitoring systems; observational datasets at a regional scale (3) Prediction and assessment: forecasting across timescales, hydroclimatic extremes, downscaling approaches, trend analyses, climate change impact assessments, and compound and multi-hazard risks; and (4) Management and solutions: water resources management, climate services, decision-support tools, and climate adaptation strategies. By fostering regional and international collaboration, this session provides a dedicated space to exchange experiences, compare approaches across diverse hydroclimatic regimes, and advance hydrometeorological science, ultimately strengthening resilience to hydroclimatic variability and change across South America.