At the request of the U.S. Army Engineer Division, Pacific Ocean (POD), a numerical model wave response study of proposed improvements to Maalaea small boat harbor was conducted by the U.S. Army Engineer Waterways Experiment Station's (WES's) Coastal Engineering Research Center (CERC). The study was conducted to determine an optimal design plan of improvement which would provide the harbor with adequate protection from the incident wave climate. The existing harbor facility consists of an entrance channel, turning basin, two protective breakwaters, 93 berths, a haulout and launching ramp, and a 100,000-lb capacity cold storage plant. Following evaluation of the existing harbor, five proposed design plans of improvement were investigated.