In the early 2000s, the sustainable seafood movement put forward the concept of fishery improvement projects (FIP), a structured multi-stakeholder approach to address environmental challenges in a fishery and aims to use the power of the market to incentivize change. The intent of the FIP model is to allow fisheries that currently do not meet the MSC standard to maintain market access while working on credible improvements. As such, FIPs have become a widely promoted approach to sustainable fisheries and have proliferated around the globe. Based on recent research assessing the impact of FIPs and testing various FIP attributes and their link to FIP performance, it seems that the FIP model may be delivering on its promise overall. However, the impact of FIP are at best based correlation rather than causation, with only few FIP attributes having been measured consistently over a significant period of time. This paper makes a theoretical contribution to understanding of FIPs by focussing on one attribute: the structure of their social network and its implication for social capital and successful collective action.