Sandy beaches are ecosystems that hold great economic value at local, national, and international level. However, their perception as social-ecological systems is often limited by users and managers to the recreational asset, and their perception of “beauty”. Such a perception bias can hamper conservation management, negatively impact the biodiversity on sandy beaches and even threaten the ecosystem services they provide. To survey this perception bias, we applied the method of netnography to analyse Instagram posts with the hashtag #sandybeach, extracting perceptions and values for nature (intrinsic, instrumental, and relational) towards sandy beaches and their ecological features. We used the concept of littoral active zone (LAZ) to define the boundaries of this social-ecological system that spans the land and the sea. Our results show that Instagram users focus on their social media mainly on the recreational values of sandy beaches and prioritise ecological features fitting into an imaginary of a “pristine” beach, characterised by white sand and clear water – therewith supporting the hypothesis about a perception bias on sandy beaches. We identified a diverse set of relational values, especially around recreation and aesthetics, with a very marginal number of posts mentioning intrinsic or instrumental values. A recurring activity on LAZ was surfing, which emphasises the LAZ (wave break point, surf zone). To conserve the biodiversity and ecosystem services of sandy beaches, we see it as necessary to move away from a biased and narrow perception to one that, based on the LAZ as a system, is capable of including a diversity of biogeographical and ecological features, and the natural processes that maintain them.