In coastal zones, the crucial factor lies in the interaction between currents and waves in the design of coastal protection and harbour sheltering structures. This study aims to explore the complexity and chaotic nature of wave-dominated turbulent flows by introducing the concepts of chaos theory. Conducted within a laboratory flume, the experiments entail two distinct tests: a steady flow test and a test with the addition of waves to the steady flow under identical flow conditions. Two chaos theory-based methods are used to examine the complexity and chaotic nature of the wave-current dynamics: The False Nearest Neighbour (FNN) method and the Lyapunov Exponent method. These methods are complemented by the continuous wavelet methods, which are employed to verify and interpret the results from the chaos theory methods. The results from the chaos theory methods suggest that there is positive evidence of the existence of chaotic behaviour in the combined wave-current flow. The complexity is found to be greater at the near-bed region with an aperiodic nature of the eddy scales. The complexity decreases when moving towards the near-surface flow region, indicating that the turbulent flow structure is less complex at the surface. The complexity for the steady flow case is high, and it decreases with the addition of the waves. The reduction in complexity is more pronounced with an increase in the wave frequency. Observations from the wavelet show the presence of the near-surface flow region exhibits isotropic and homogeneous turbulence structures, indicating the existence of periodic and organized flow structures. The results demonstrate that the addition of waves to the steady flow alters the turbulence characteristics of the flow and introduces periodic and organized flow structures. The implications of these findings are significant for wave dynamic monitoring, modelling, and forecasting. This study provides insights into the complexity and chaotic nature of wave-dominated turbulent flows, which are essential for proper design and management of coastal protection and harbour sheltering structures. In conclusion, the study introduces chaos theory concepts to examine the complexity and chaotic nature of surface-generated waves in comparison to steady flow states. The results demonstrate that the addition of waves alters the turbulence characteristics of the flow, resulting in periodic and organized flow structures. The findings have important implications for wave dynamic monitoring, modelling, and forecasting, providing a foundation for improved design and management of coastal protection and harbour sheltering structures.