In this study, we will compare the effect of normal clothes (assumed as bare skin) with effect of wetsuit in maintaining the core body temperature, produced by metabolic heat generations and blood flow heat generation, using COMSOL. A passenger is immersed in cold water after Titanic has shipwrecked, and the individual is waiting for rescue to come in time before his metabolic functions stop and die. We will compare two cases: with and without wetsuit on the passenger. Skin temperature or wetsuit temperature is assumed to be equal to cold water temperature, which is at 10 degrees Celsius, and the distribution of temperature throughout the body will be graphically shown as the time of body immersion in water increases. It is shown from the results that wetsuit can help maintain the normal core body temperature much longer than normal clothes/bare skin can in cold water immersion.