This paper presents the Support Vector Regression (SVR) to predict the stability number of armor blocks of breakwaters. The experimental data of van der Meer are used as the training and test data for the SVR in this study. Estimated results of SVR are compared with those of the empirical formula and a previous Artificial Neural Network (ANN) model. The comparison of results shows the efficiency of the proposed method in the prediction of the stability numbers. The proposed method proves to be an effective tool for designers of rubble mound breakwaters to support their decision process and to improve design efficiency.