CO2 ocean disposal is one of several ways proposed to mitigate the greenhouse gas effect. In this paper, we estimate the cost of various CO2 disposal options. The system consists of a conventional pulverized coal power plant, CO2 separation using an amine scrubber, liquefaction and transportation. In this investigation, the power plant and the CO2 separation plant are common. The liquefaction process and transportation systems are different. We evaluate the costs of pipeline, liquid CO2 tanker for CO2 lake, liquid CO2 tanker dispersion, dry ice tanker and CO2 dispersion by OTEC. The effect of distance between a power plant and the disposal site, plant size, and plant efficiency on the cost for each case is evaluated. Costs of ocean disposal options are estimated about 90 to 180 per tonne of CO2 avoided. The least cost transportation option is dependent on the distance between power plant and site.