Freshwater ecosystems have undergone dramatic changes in the past centuries and it will be a decisive task to undo the damages incurred while saving the last intact habitats from further degradation. The present legal framework offers great opportunities for new restoration efforts – with the newly implemented Nature Restoration Regulation catalyzing a range of measures including reconnection efforts at stream network level, revitalisation of entire floodplains, and rewetting of once water-logged land. However, while we increase the restoration knowledge base and celebrate successes, we also learn about the limits, with cases where biodiversity hasn´t come back yet despite physical habitat recreation, or where functioning does not rebound in parallel with biodiversity. Further, implementation of restoration efforts poses a significant challenge to modern societies, i.e. understanding ecology is not enough when stakeholders disagree, and finding the societally most sustainable solution is not often easy and requires an inter- and transdisciplinary effort.  Our attempts to achieve long-term restoration of biodiversity and ecosystem functioning critically depend on the existence of remaining natural or near-natural habitats and intact migration corridors. Protecting these will be key as they act as refuges and sources for recolonization, serve as reference systems, and protect mankind from baseline drift. Yet, biodiversity loss also takes place in presumably intact systems, and the mechanisms at work must be better understood. These include pressures acting at different scales, from local to global, as well as our readiness to subordinate healthy ecosystems to presumably more important developments, e.g. renewable energy production. In this context, compensation measures must be evaluated critically. Even the best restoration is unlikely to to compensate for the destruction of a healthy and well-functioning ecosystem. The motto must be: first conserve what we still have and restore what we have lost? Future freshwater ecosystem management will thus need (i) disciplinary expertise for successful restoration, (ii) conservation of natural systems, but also (ii) moral courage to argue for the benefits of restoration and to speak up against continued assaults on intact ecosystems. The goal of this session is to highlight the significance of freshwater ecosystems and outline trajectories for maintaining and restoring their biodiversity as well as their functioning.