Surfing provides an excellent case study for power of extra-legal social norms to efficiently regulate public resources. A complicated, cross-cultural set of cooperative norms governs surfers’ behavior in the water. These norms promote safety and the efficient sharing of a natural resource: waves. As an ever increasing number of surfers compete for this fixed resource, conflict has become more common and the cooperative norms of surfing are sometimes replaced by the exclusionary practice of “localism.” Nevertheless, attempts at formal regulation of surfing have failed and surfing is still governed almost entirely by social norms.