Public support of mussel farming in Greece is an important factor because of its financial viability. The profitability of the activity is seriously reduced in small farms (1–3 ha) as a result of their high production costs; however, small farms represent a major part of the industry. Mussel farming is an extensive activity, with space availability regulated by public administrators via licensing of marine cultivation area property rights. The available space, though, is limited and, consequently, impedes any future expansion, restricting the production capacity of small farms. Nevertheless, the cost of new establishments and the modernization of existing ones (suitable boats, grading equipment, and so on) is affordable only by the larger companies. For small farms, it seems harder to recruit the large labor teams needed to work on a seasonal basis because this is the optimum to effect least operational costs, as shown by sensitivity analyses. In conclusion, for financial sustainability this sector needs to be restructured and organized into larger schemes, such as with producer organizations or cooperatives, to achieve economies of scale.