Indonesia, the world’s largest archipelagic country, lies between the Pacific and Indian Oceans, making it a critical region for studying oceanographic and climate processes. Understanding these dynamics requires long-term, continuous observations. However, coastal monitoring in Indonesia remains fragmented, with data scattered across regions and institutions. This study compiles information from multiple sources, including research institutions, international initiatives, official repositories, and national monitoring programs. A total of 550 coastal monitoring sites were identified, covering diverse measurements with varying levels of data quality and availability. Analysis of temporal coverage reveals that most sites are short-term: 81 stations (<2 years) and 185 stations (2–5 years). Only 45 stations (5–10 years) provide mid-term records, while none extend beyond 10 years. Furthermore, 239 stations lack sufficient metadata to determine monitoring duration, reflecting persistent challenges in data management and accessibility. The distribution highlights significant gaps in Indonesia’s coastal observation capacity. While short-term datasets support localized studies and project-based assessments, the absence of long-term (>10 years) time series restricts the ability to detect climate-driven trends, seasonal variability, and ecosystem responses. The imbalance is also spatial, with more coverage in western Indonesia compared to eastern and remote areas. Strengthening Indonesia’s coastal monitoring requires coordinated efforts to extend observation durations, promote standardized measurement protocols, and enhance open access data sharing. Establishing sustained monitoring sites would not only improve national capacity but also support global initiatives under the UN Ocean Decade and the Sustainable Development Goals, ensuring science-based management of marine resources in a changing climate.