One of the technological devices that can be used to generate electricity from ocean waves is the Oscillating Water Column (OWC) system. This system utilizes the rising and falling motion of the water in the air column to turn turbines and generate electricity. The purpose of this research is to find out the amount of electrical power generated by the prototype with a width of 0.5 m at 4 variations of the back wall slope and 3 variations of the wave height and 4 variations of the wave period. The test results on the towing tank showed that the best period is 2.4 seconds and the optimal back wall slope is 15°, where the wave height of 0.066 meters, 0.1 meters, and 0.133 meters is capable of producing electrical power of 0.25 Watt, 0.68 Watt, and 1.26 Watt respectively. This study also obtained that the greatest efficiency in the water column was 1.30% and the total efficiency of the SWPP-OWC prototype was 0.56%