This chapter investigates how variations in floater geometry can influence the key hydrodynamic parameters, such as added mass, radiation damping, RAOs, excitation forces, and PA-WEC’s power performance under isomorphic design criteria. It discusses the numerical code, computational scheme, and hydrodynamic performance assessment methods of the S-class and SB-class floaters. A comparative assessment was performed for these floaters, and their shape-change effects on the PA-WEC’s power absorption were studied to develop a roadmap for designing the unconventional floater geometries for optimal power absorption. The ANSYS AQWA simulation results were also validated against lab-scale wave tank test results. The potential effects of added mass, radiation damping, and PTO characteristics on the Response Amplitude Operators (RAOs), power absorption, and efficiency of the PA-WECs were described under irregular waves. The performance of the floaters was analyzed, and the optimal floater design with maximum power absorption in both regular and irregular wave conditions, under optimal and suboptimal WEC modes, was identified through experimental verification of simulation results. Their costs and performance were also balanced to demonstrate their feasibility for real-world deployment.