This paper sought to identify the degree of seasonality of 18 national parks sing monthly visitors data. It also endeavored to determine whether the shape of seasonal variations(CVt) are converging, diffusing, or showing a stationary phase. Several 12 month-centered methods that have a moving average were used to remove seasonality and to find variations over periods of January 1987 thru December 2002. The coefficients of variation were adopted to discern the changing and shifting rates of national parks. The main measurements applied to the analysis were in terms of national parks, month, areas, and types of sightseeing trip. Results indicated that the amount of seasonality still exists, but its degrees or levels show a stationary phase for a few parks such as Mt. Bukhan, Keyong, which is located in the city. Likewise, exploration for Mt. Bukhan was found to project a stylized image for the park rather than that of seashore. Finally, this paper found that sightseeing of Korean national parks take place in August and October.