High dependence on fishery resources has an impact on the economic vulnerability of fishermen's households due to seasonal fluctuations, market prices, and environmental changes. This study aimed to identify the socio-economic, technological, and institutional characteristics of fishermen, assess the contribution of tuna fishing to household income, and formulate income diversification strategies for fishermen in Tehoru District, Central Maluku Regency. The study was conducted in January–March 2024 in Haya and Tehoru Villages, involving 40 respondents selected through purposive sampling. Data collection methods included surveys, in-depth interviews, observations, and secondary data review. The results showed that fishermen were dominated by the productive age group (21–40 years), with secondary education and 6–10 years of work experience. Fishing technology is still traditional with handlines, and fishing activities are highly dependent on the season. The contribution of tuna fishing to total household income reached 88.2%, while diversification through fish processing (5.28%) and non-fishery businesses such as plantations and services (6.52%) functioned as a buffer during the lean season. Recommended strategies include environmentally friendly technology training, diversification of processed products, strategic partnerships, and integration of marine tourism. Sustainability efforts require multi-party collaboration to strengthen economic adaptation and fishermen's resilience to environmental changes.