Coastal ecosystems are important to rural, coastal communities in many low-income countries. For example, fishing provides nutrition and income. Gleaning is a type of fishing that involves collecting edible plants and animals in shallow areas at low tide. Interactions with local environments through activities like gleaning can be important to people because they represent meaningful relationships with nature. However, we understand very little about how, why and when people interact with coastal ecosystems through gleaning. We studied what seasons people gleaned in and why, and how seasonal gleaning contributed to seafood consumption in eight coastal communities on Atauro Island, Timor-Leste. We used surveys from 128 households on the types of fishing (including gleaning) carried out in seasons of calm and rough seas. We also asked how often households ate seafood in each season. We combined this information with data on the type and size of shallow coastal habitat close to each community. We found that some households never gleaned, some gleaned in one season, and others gleaned in both seasons. Households that gleaned during the rough season had more stable seafood consumption between seasons than those who did not. We also found that shallow habitat mattered. In the calm season, more households gleaned where areas of shallow habitat were bigger. In the rough season, habitat type also became important, and where shallow habitat was mostly hard, such as coral reefs, communities were more likely to glean than where shallow habitats were mostly soft, such as sand. In communities with soft shallow habitat, many households only gleaned in the calm season because rough weather makes the water less clear and it is harder to find seafood. These results show that how and when people interact with coastal ecosystems by gleaning differs because habitat affects the feasibility and desirability of seasonal gleaning. A context-specific understanding of how people interact with coastal environments is therefore important. Specifically, our findings show that amongst communities and seasons there are differences in pressure on coastal ecosystems from gleaning, the ability of households to benefit from gleaning and the role of gleaning in adapting to seasonal food insecurity.