In this paper, we conduct a sensitivity study to investigate the difference between time-domain and frequency-domain modeling of small-sized, two-body point absorbers using the modeling software ProteusDS. Frequency domain analysis has an advantage in that it provides fast evaluations and has been used widely in this field; however, its reliance on linearized assumptions may be inadequate for smaller-sized WECs. A nonlinear, time-domain model is able to account for the nonlinear buoyancy variation and nonlinear hydrodynamics, but will increase computational complexity. To compare the fidelity of these models within this context, three float shapes of increasing complexity are evaluated in a full 6 degrees of freedom. It is important to note that the definition of the term ‘smaller-size’, which refers to WEC devices whose characteristic dimension is of the same magnitude as the mean wave height (around 1 meter). Devices of this size will have short natural periods and will have large wavedriven excursions when exposed to open ocean conditions, and as such will be operating in highly nonlinear conditions. These conditions are analogous to the extreme conditions that a larger-sized WEC would experience— WECswhich would typically be designed to have a limited (reduced) response. Our results show that numerically modeling small-size WECs does require nonlinear assumptions to accurately capture the nonlinear forces acting on the WECs in large, nonlinear wave conditions the smallsize WECs would typically be operating in.