During the last decade, surveys and small-scale excavations at a peat extraction site in the bog Dagsmosse, Östergötland, east Central Sweden has unearthed a series of Mesolithic sites with well preserved organic remains. The encountered sites varies in character, while some can be classified as settlements, other are best described as activity areas, either on the shores or on the bottom of the former lake. The activity areas include both short-term sites like the spot where a specific animal was butchered, others contain the remains of repeated activities like fishing with nets, bone leisters or wooden fish traps. The material from the Dagsmosse complex, complemented by isotope data from the surrounding region, is discussed in relation to local, regional and global environmental changes.