In many islands of the South Pacific there is evidence of positive conservation outcomes founded upon community-based environmental management (CBEM) of marine biodiversity. But community based initiatives need to be supported by legal frameworks to facilitate and strengthen them as well as to address specific issues of legitimacy and enforcement. While recognising the need for a legal framework, there is little guidance available to the law and policy-makers who are charged with drafting effective laws to facilitate marine governance. This paper considers the legal frameworks that support CBEM in the region and, in particular, the role of customary law. The experiences of the Fiji Islands, Samoa and Vanuatu are investigated here as they may be of assistance to other SIDS seeking to establish similar cross-cultural environmental law regimes.