Governance across the land–sea interface presents many challenges related to (1) the engagement of diverse actors and systems of knowledge, (2) the coordinated management of shared ecological resources, and (3) the development of mechanisms to address or account for biogeochemical (e.g., nutrient flows) and ecological (e.g., species movements) interdependencies between marine and terrestrial systems. If left unaddressed, these challenges can lead to multiple problems of social-ecological fit stemming from governance fragmentation or inattention to various components of land–sea systems. Network governance is hypothesized to address these multiple challenges, yet its specific role in affecting social-ecological fit across the land–sea interface is not well understood. We aim to improve this understanding by examining how network governance affects social-ecological fit across the land–sea interface in two empirical case studies from the Lesser Antilles: Dominica and Saint Lucia. We found that network governance plays a clear role in coordinating management of shared resources and providing capacity to address interactions between ecological entities. Yet, its potential role in engaging diverse actors and addressing, specifically, biogeochemical interactions across the land–sea interface has not been fully realized. Our research suggests that network governance is beneficial, but not sufficient, to improve social-ecological fit across the land–sea interface. Strategically leveraging the network processes (e.g., triadic closure) leading to the existing governance networks could prove useful in addressing the current deficiencies in the networks. Additionally, the interplay between hierarchical and networked modes of governance appears to be a critical issue in determining social-ecological fit at the land–sea interface.