Extensive temperature readings were obtained to determine suitable OTEC power plant sites in the Philippines. An analysis of temperature profiles reveals that surface seawater is in the range of 25 to 29°C throughout the year while seawater at 500 to 700 m depth remains at a low temperature of 8 to 4°C, respectively. In this article, 14 suitable sites within the Philippine seas are suggested. Conceptual designs for a 5-MW onland-type and a 25-MW floating-type OTEC power plant are proposed. Optimum conditions are determined and plant specifications are computed. Cost estimates show that a floating-type 25-MW OTEC power plant can generate electricity at a busbar power cost of 5.33 to 7.57 cents/kW·h while an onshore type 5-MW plant can generate electricity at a busbar cost of 14.71 to 18.09 cents/kW·h.