Regional connectivity plays a crucial role in supporting economic growth, especially for areas that are geographically remote or separated by bodies of water. As an archipelagic country, Indonesia heavily relies on sea transportation as the main axis of its maritime logistics routes, which connect various regions and support the distribution of goods as well as the mobility of people. Therefore, planning and developing transportation networks require accurate measurements, such as the connectivity index, to understand the extent to which a region is connected to others. This study aims to analyze the regional connectivity index of the islands in South Halmahera Regency, North Maluku, using a graph method approach. This method is employed to evaluate how well the districts in the regency are interconnected through sea routes. The results show that overall, maritime connectivity between regions in South Halmahera Regency is fairly good. From the analysis, 13 districts have a connectivity index of > 1, indicating good connectivity, while 17 districts have an index of < 1, indicating limited connectivity. These findings suggest a disparity in connectivity between regions in South Halmahera, highlighting the need for efforts to improve infrastructure and sea transportation networks to enhance inter-district connections, especially in areas with low connectivity indices.