This paper examines the relationship between visitors' perception towards tourism impacts and post-perception behavior in Horizon Festival of Donghae City, one of the regional ocean festivals. In this paper the post-perception behaviors (related to one's intention of revisiting the ocean festival) and tourism impacts are both independent variables in the research model. The hypothesis advanced are identified as follows: Firstly, the economic impacts of tourism have a positive affect on post-perception behavior. Secondly, environment impacts of tourism also have positive affects on post-perception behavior. Thirdly, socio-cultural impacts of tourism have both a negative and positive affect on post-perception behavior in. That is to say that visitors who have positive tourism impacts will intend to visit to ocean festival and famous tour sites near by while people with negative tourism impacts are less likely to visit the festival and regional destinations. Therefore, the festival manager and tourism marketer should in first hand examine the visitors' tendency towards tourism impacts and based on the examination, build marketing strategies for attracting visitors.