Hunter-gatherer wetland sites in boreal Fennoscandia are rare, deeply buried, and difficult to detect, making them a still critically underutilised archaeological resource. However, the moist anoxic conditions of waterlogged contexts preserve organic materials that are typically lost on boreal drylands, thus offering unique tools to explore the past. Small-scale excavations in 2020–2021 at the wetland site of Järvensuo 1, southwest Finland, uncovered a stratified lakeshore archive spanning over five millennia and a rare assemblage of organic artefacts, structures, faunal remains, and environmental data. The discoveries, characterised by sustained and repeated utilisation of freshwater resources, reveal long-term human occupation and activities by a small lake from the Late Mesolithic to the Final Neolithic (c. 6000–2000 cal BCE). This paper synthesises the fieldwork results, contextualises the findings, and examines the significance of similar lake environments in understanding hunter-gatherer subsistence, landscape use, and cultural practices in Fennoscandia and northeast Europe.