Aquatic foods are important contributors to food and nutrition security, dietary quality, and livelihoods across Pacific Island coastal communities. However, experiences from earlier Pacific aquaculture initiatives demonstrate that introducing new livelihood opportunities without consideration of gender roles, resource access and decision-making can unintentionally shift labour and economic benefits away from women, reducing their participation in higher-value and income-generating nodes of the value chain 1. Given the established links between women’s resource control, household food security, and nutrition outcomes, understanding gendered pathways within developing mariculture systems is critical for equitable and nutrition-smart development. This study aimed to explore gendered roles, decision-making pathways, and access to food and income benefits within Fijian coastal food systems, to inform emerging seaweed and rock oyster mariculture enterprises that strengthen rather than diminish women’s participation and agency. Guided by the Women’s Empowerment and Market Systems framework, a mixed-method study was undertaken with 85 participants (28 women, 31 men and 26 youth) across three iTaukei coastal communities in Fiji. Gender- and youth-segregated Talanoa discussions, photo elicitation activities and enumerator-administered surveys were used to explore roles, aspirations, decision-making and access to resources within aquatic food systems. Particular attention was given to women’s contributions to aquatic food harvesting, marketing, household food provision and decision-making. Women were found to play central roles in coastal food systems through shoreline harvesting, seafood processing, food preparation and marketing activities. Despite these contributions, women reported more limited access to training, productive assets, and formal decision-making structures, influencing livelihood development. Participants identified seaweed and rock oyster farming as opportunities to strengthen income generation, local food availability and community wellbeing. However, they emphasised the importance of culturally appropriate governance, locally led approaches, and community capacity building that support women’s participation, leadership and equitable benefit sharing. Nutrition-smart mariculture development requires attention to the social, cultural and gendered factors that shape access to food, income and livelihood opportunities. Participatory approaches such as Talanoa and photo elicitation revealed pathways to strengthen women’s agency and collective empowerment, while informing the co-design of emerging mariculture enterprises. Findings highlight that equitable seaweed and rock oyster development must move beyond technology transfer to ensure women remain visible and influential across value chains, thereby supporting food security, nutrition and sustainable livelihoods in Fijian coastal communities.