International Maritime Organization (IMO) has implemented the Energy Efficiency Design Index (EEDI) verification to reduce greenhouse gas emissions. The air lubrication method, which reduces the frictional resistance of the ship by supplying air to the hull surface, is one of the most efficient methods in terms of ship operation and eco-friendliness. In this study, a computational fluid dynamics analysis of a flat plate was conducted to identify the main factors affecting the air layer characteristics and cavity formation in the air cavity. Coupled Level Set and Volume-of-Fluid (CLSVOF) that combines only the merits of the Volume-of-Fluid (VOF) method that preserves the mass of each phase well and the Level Set method that accurately calculates the curvature of the phase interface was used to accurately calculate the interface between bubbles and liquids. The air lubrication of the plate was analyzed and the frictional resistance according to the air lubrication was compared with the experimental results.