This study depicts the increasing vulnerability of Maio’s (island of Cape Verde’s archipelago) small-scale fishing communities that rely directly on rich but declining fish stocks. The concept of mobility is defined in this paper to describe inward and outward flows of resources, people, species, and governance. Mobility is a useful tool for studying small-scale fishing communities, as it enables environmental, economic, and political factors that shape vulnerability to be analyzed on the same footing. While most elements flowing outward from Maio and surrounding waters are beneficial (e.g., fish catches and local governance capacity) and most flowing inward are detrimental (e.g., foreign industrial vessels, international interference, and greenhouse gas), the overall result is increasing vulnerability for local communities. Maio is concomitantly very dependent on the unstable and intermittent inward flow of some elements, such as fuel, food, and international aid. The Actor in 4 dimensions (A4D) methodology (in-depth interviews regarding residents’ and experts’ perceptions of their marine environment and its governance) allows a comparison to be made between the perceptions of vulnerability and facts (provided by official documents and a scientific literature review). The A4D results namely indicate that locals hope for better fishing and marketing equipment and infrastructure that would improve their commercial mobility. Interviewees also ask for stronger local, national, and regional self-governance and law enforcement to protect their sea resources.