The French population, and particularly the population of Brittany, is fond of shellfish. However, their consumption can lead to outbreaks of foodborne illness, the incidence of which—as estimated by mandatory reporting—is likely underestimated. The objectives of this pilot study were to quantify and describe the health impact of shellfish-related foodborne outbreaks as well as the circumstances of their occurrence among the working population of Brittany, with the aim of eventually reducing their frequency. A multicenter cross-sectional descriptive study was therefore conducted among staff members of Lorient Agglomération, the École des hautes études en santé publique, and the Agence régionale de santé Bretagne. One thousand four hundred forty-four people were surveyed between May and July 2022 via an online questionnaire. The questionnaire explored shellfish consumption between November 1, 2021, and April 30, 2022 (the period of interest), the practice of beachcombing, and the occurrence of shellfish-related foodborne illness over the past five years. A second section was used to describe episodes of shellfish-induced food poisoning that occurred during the period of interest (symptoms, meals, etc.). A total of 438 responses were received (response rate: 30%). The majority of respondents were women (70%), the median age was 46 years, and 21% engaged in beachcombing. During the study period, 93% of respondents reported having consumed shellfish. Scallops (80%) and mussels (76%) were the most commonly consumed. Finally, 38 respondents (9%) reported at least one episode of shellfish-related foodborne illness between 2017 and 2022. During the study period, 9 episodes of foodborne illness were reported by 9 respondents (2%), including 8 episodes in which raw oysters had been consumed. This pilot study supports the hypothesis of significant underreporting of shellfish-related foodborne illnesses at the regional level (and therefore likely at the national level). Further analysis is warranted to better quantify the health impact of shellfish-related foodborne illnesses with the aim of informing the shellfish industry and stakeholders responsible for coastal waters.