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The effects of river restoration on hydromorphological conditions and variability are often documented immediately following the restoration, but rarely properly monitored in the long term. This study assesses outcomes of 20 restoration projects undertaken across central and northern Europe for a comprehensive set of hydromorphological parameters, quantified at both larger and smaller spatial scales. For each project, we compared a restored river section to an upstream degraded section. Ten pairs of large projects were contrasted to ten similar but less extensive projects, to address the importance of restoration extent for the success of each project. Overall, river restoration increased habitat diversity through changes in channel morphology. Our results indicated that restoration particularly improved macro- and mesohabitat diversity, but had a limited effect on microhabitat conditions, including the diversity …