Chellanam Harbour, located on the south west coast of India, is a fishing village withmechanised fishing operations, yet it is increasingly hindered by sediment accumulation that restricts navigation and disrupts daily activities. This study applies the MIKE21 LITPACK numerical modelling suite, developed by DHI, to investigate sediment transport pathways and evaluate wave conditions influencing Chellanam harbour tranquillity. Bathymetric inputs were obtained from GEBCO, while hydrodynamic and meteorological forcing were sourced from ERA5 reanalysis products. Simulations conducted within the MIKE21 Toolbox mapped spatial and temporal patterns of sediment deposition, identifying an average annual siltation rate of 0.144 m, with the most rapid build-up occurring in the entrance channel. This area is critical to safe vessel manoeuvring. The findings offer a predictive framework for optimising dredging cycles, improving sediment management, and guiding infrastructure modifications to sustain operational efficiency. While grounded in a specific regional context, the methodology is transferable to other small tropical harbours worldwide, where similar challenges are magnified by climate-driven changes in coastal processes. By linking applied coastal engineering with global resilience objectives, this research supports UN Sustainable Development Goals on climate action, sustainable fisheries, and resilient infrastructure, contributing to the long-term viability of working waterfronts in developing maritime economies.