1200 GT Coaster Vessel is designed to mobilize the flow of goods and passengers in order to implement the Indonesian Sea Toll Program. This vessel is necessary to be analysed its stability to ensure the safety while in operation. The stability is analysed, firstly by theoretical approach (preliminary stability) and secondly, based on inclining test data to derive the final stability. The preliminary stability is analysed for the estimated LWT of 741.20 tons with LCG 23.797 m from AP and VCG 4.88 m above the keel. On the other hand, the inclining test results present the LWT of 831.90 tons with LCG 26.331 m from AP and VCG 4.513 m above the keel. Stability analysis on for both data is performed by considering the standard reference of IMO Instruments Resolution A. 749 (18) Amended by MSC.75 (69) Static stability, as well as guidance from Indonesian Bureau of Classification (BKI). Results of the analysis indicate that the ship meets the stability criteria from IMO and BKI. However results of preliminary stability analysis and final stability analysis exhibit a difference in the range 0.55% to 11.36%. This put forward better result from the final stability analysis due to the less accuracy in preliminary stability computation.