Background: Despite the abundance and proximity of edible marine resources, coastal communities along the St. Lawrence in Eastern Quebec rarely consume these resources. Within a community-based food sovereignty project, Manger notre Saint-Laurent (Sustenance from our St. Lawrence), members of participating communities (three non-Indigenous, one Indigenous) identified a need for a web-based decision tool to help make informed consumption choices.Objective: To co-design a prototype website that facilitates informed choices about consuming local edible marine resources based on seasonal and regional availability, food safety, nutrition, and sustainability.Method: We co-designed a prototype with community members, regional stakeholders, and experts in user experience design and web development. We conducted 48 interviews with a variety of people over three iterative cycles, assessing the prototype’s ease of use with a validated measure, the System Usability Scale.Results: Community members, regional stakeholders, and other experts identified problematic elements in initial versions of the website; for example, confusing symbols. We resolved issues and added features people identified as useful. The final prototype’s usability was rated at “best imaginable” with scores similar across socio- demographic groups.Conclusion: By co-designing with community members, regional stakeholders, and other experts from the beginning, we were able to integrate communities’ priorities and perspectives about edible marine resources into a prototype website adapted to community members' needs. The final prototype includes a tool to explore species, and index cards to regroup accurate evidence about food safety, nutrition, sustainability, regional and seasonal availability, taste properties, and responsible fishing, hunting, picking, and preparation methods.