Skateparks on the map: over 450 skateparks and BMX tracks in Finland, browsable by municipality. Free, no sign-up, no account and no paywall.
493 places in
Most skateparks are in Helsinki (32), Espoo (17) and Vantaa (16). The full list is below by municipality, and the map can be filtered to your own area.
The remaining places are on the map and in the municipality list.