The self-propulsion simulations of JBC (Japan Bulk Carrier) were performed in model and full scale with two approach: one is the body force method using steady blade element theory (lift lines theory) and infinite blade propeller, the other is 3-D discretized propeller method. All simulations were investigated using an in-house CFD code which is based on the finite difference method to discretize the governing equations. A dynamic overset technique was used and any revolutions of the propeller can be achieved in the simulation. In order to obtain the self-propulsion point, a PI speed controller was utilized to adjust the rate of revolutions of the propeller. To obtain self-propulsion factors, resistance and open water tests are also computed. Thrust identity method was used to obtain wake fraction. The full scale total resistance coefficient was obtained according two extrapolation methods: the first is the ITTC 1978 recommended procedure, while the second is the extrapolation method based on Grigson friction line. Wake fraction was revised following ITTC recommended procedures in full scale. All the results of the simulation have a reasonable agreement with experimental results. The computational results presented in this paper also provide evidence to the full scale self-propulsion prediction ability of the in-house code.