This study presents comprehensive wave tank model testing and analysis for the proposed Lindeman Island Floating Jetty in Queensland, Australia. Using a 1:25 scale model, we investigated wave-structure interactions under extreme scenarios combining 500-year and 50-year Average Recurrence Interval (ARI) wind and tide events. Our methodology integrated global computer modelling, local Computational Fluid Dynamics (CFD) simulations, and physical wave tank tests, incorporating high-resolution bathymetric data. Results indicate that the 50-year ARI wind combined with 500-year ARI water level produces the worst-case wave loads, with maximum residual wave heights reaching 3.06 m in full-scale equivalent. The study revealed significant load variability, with peak horizontal forces (Fx) of 1288.59 kN and vertical moments (Mz) up to 15,070.73 kN·m in the worst-case scenario. The unique Z-shaped bathymetry was found to play a crucial role in wave transformation, leading to a 39.2% increase in horizontal force under submerged conditions. This research provides critical insights into load variability, submerged state effects, and the impact of tidal variations on wave dynamics, offering valuable design inputs for the floating jetty. The hybrid approach employed demonstrates the effectiveness of combining numerical modelling with physical testing for complex marine environments, contributing significantly to the field of coastal engineering and floating structure design.