A method for analyzing reflection and transmission of ocean waves from a semi-infinite elastic plate with a draft is developed. The relation of energy conservation for plates with three different edge conditions (free, simply supported and built-in) is also derived. It is found that the present method satisfies the energy relation very well. The effects of draft on wave reflection and transmission coefficients as well as on the vertical vibration of the plates are examined through numerical tests. It is demonstrated that the zero draft assumption works well for low wave frequencies, but the effect of plate draft becomes significant for high wave frequencies. A method for analyzing reflection and transmission of ocean waves from a semi-infinite elastic plate with a draft is developed. The relation of energy conservation for plates with three different edge conditions (free, simply supported and built-in) is also derived. It is found that the present method satisfies the energy relation very well. The effects of draft on wave reflection and transmission coefficients as well as on the vertical vibration of the plates are examined through numerical tests. It is demonstrated that the zero draft assumption works well for low wave frequencies, but the effect of plate draft becomes significant for high wave frequencies.