Where to Find and Catch Frogadier
From Pokemon Go Wiki
Frogadier are found and captured in Nest and Habitat locations.
Nests
Frogadier Nests are locations that consistently spawn Frogadier.
Habitats
Frogadier Habitats are spawn locations where Frogadier is likely to be encountered, but not guaranteed the way a Nest is.
Additional Tips and Information
Best Nests
If you know a really good nest or any of the nests above is really good, list them here: