https://inspire-wms.maanmittauslaitos.fi/inspire-wms/HY/ows?service=wms&request=GetCapabilities

From the dataset abstract

NLS-FI INSPIRE Hydrography Theme Dataset is a dataset depicting the Hydrography Physical Waters covering the whole of Finland. It contains the following INSPIRE feature types: Dam Or Weir, Land-water Boundary, Rapids, Shoreline Construction, Standing Water, Watercourse.

The elements are updated approximately every 5–10 years. The dataset is based on the NLS Topographic database:

https://www.paikkatietohakemisto.fi/geonetwork/srv/eng/catalog.search#/metadata/cfe54093-aa87-46e2-bfa2-a20def7b036f

The dataset is available via the NLS-FI INSPIRE Download Service (WFS) for Hydrography Theme and it can be viewed via NLS-FI INSPIRE View Service (WMS) for Hydrography.

http://paikkatiedot.fi/so/4dae5686-2a8c-40d8-837f-ce6f5547dba2

Source: NLS-FI INSPIRE Hydrography Theme Dataset