Karimunjawa National Park is one of the national parks that have the objective to maintain fish populations in the Java Sea, where one of them is grouper. Grouper is one of the target fish in the national park. The objective of this study is to assess the conditions and dynamics of the grouper fishery in Karimunjawa National Park. Fish landing surveys were conducted to collect the data. Fishing gear types, grouper species, and weight of each species were collected. Calculation of Catch per Unit Effort (CPUE) per month and two-way ANOVA statistical tests were used for data analysis. Results of this study indicated that catches of grouper using speargun was significantly higher than the catch using handline. There was a seasonal cycle of the grouper catch, where the value of the highest CPUE occurred in transitional season between the west and east monsoon season, from March to May.